Heard of.

About fifty miles away from our site.

Also I've heard this deficit.

Spending projects more than.

Six bucks in the hole so existing.

For among others.

But also a life who remind the future
of science is not only a child.

Entering the room it's
also a scientific telling.

The Israelis.

And it.

Does only through a large
set of conclusions from.

Relation based on experience the results
of a computer of activities like.

Direct.

Others.

There are also other brainchild.

There are many.

Theories.

And today we have the pleasure of.

Professor Richard.

Member and
former director of the group for studies.

Well The Guardian and on the record
last night this particular model of

course there are over six.

Now that share a good part.

Of Texas at Austin.

And he has a major contribution.

To this next one which
transport you really.

Know your mother.

If you have to I think that's
the leading expert in this field.

It's just.

Important and
challenging problems thank you.

But really delicious day talking to
colleagues in the department and

learning about exciting thing going here
really really great great experience.

This is just saying to someone this is
a talk not about things I've done but

about things I've heard and that's a come
down and kind of a said change in my life

so I will see if I cope with it or
if I start sobbing in the middle of it.

It really is a news report so I'm telling
you I'm going to tell you what's going on

in fusion nowadays in the in the U.S.
fusion program and it will be my own.

Perspective and on the theorist so
it's probably a distorted might be

a distorted perspective.

So that's.

What it's about actually this
outline is incomplete there's also.

The numbering is funny to this from going
to start out with a short course in fusion

much I hope doesn't insult people but just
a few slides how fusion supposed to work

up magnetic fusion is supposed to work and
then there's this survey and

there's this comment I have of.

This comment that.

Area.

Plasma Physics as I think most of you
know is a very exciting dynamic area

of research or a growing area of research
especially proud of my astrophysics

and pasta physics is actually
quite delicious and.

I wish you know I resisted
the temptation to put in five slides

about the excitement of plasma physics.

Fusion.

Physics is.

A part of plasma physics and you can judge
at the end of the talk how exciting you

think it is but of course the fusion
program is more and more being

dominated by engineering issues and
by large scale simulation.

So I'm going to give you this survey and
then I hope

that there's some time to talk about more
fun things to very specific concrete

interesting initiatives
going on in the program.

And here's the short course that I
advertised so again forgive me if this is

insulting but this is a plot
of stored energy in an atomic

nucleus as a function of nuclear mass and

the punchline which you probably all know
is that everything wants to be iron and

iron is the real.

Equilibrium state have a nucleus
somewhere in the vicinity of iron.

And when you get heavier elements there's
more energy free energy available and

similarly lighter elements
have free energy available but

there's a disparity between
the two the amount of energy.

Available and.

Nuclei that are too small is huge compared
to the amount stored in nuclei that

are too large and that's why
usually starts to look interesting.

So that.

Stored energy all has to do with
the nuclear force which is very short

range as you know strongly attractive.

Light elements want to join want to fuse
with each other get to a lower energy

state but
they have to contend with the cool

force the these are nuclei all
nuclei are positively charged.

And so they repel each other before they
know about how much they're going to

like each other OK and
that's that what's called the barrier.

And to overcome that barrier
requires an enormous

energy they have to be approaching I have
a D.N.A. T. here that's a Deuteronomy and

a try time to isotopes of
hydrogen that most easily Hughes.

They have to approach each other at
huge speeds in order to get past this

barrier the repulsive Coolum force.

And when you get nuclei or atoms that

at the necessary energies
on hundred million degrees.

You don't have an ordinary
gas anymore the electrons

are completely unbound from the nuclei.

And so
you have a gas of of ions the nuclei and

lecture on separate independent gases
Well not really independent but

very they interact with each other but

they no longer are bound as they're
no longer bound into atoms and

that gives rise to a very dynamic.

State of matter.

Called plasma.

And you know it's in
the fluorescent lights in this room

stars are made out of plasma
most of interstellar.

Space is plasma.

And.

Lightning is Pozner OK so
what we need to do.

Is hold this very hot plasma
together long enough for

appreciable number of fusion reactions
take place and that's the challenge.

Of fusion energy.

You could also say well.

They they have mass these
nuclei They're massive and

therefore they can't separate from each
other instantaneously because of that

mass So if we just crammed together and
then let them

expand maybe they will
not expand fast enough.

To prevent fusion that requires
streaming high density

that's how a nuclear explosive works
you cram these nuclei together.

At such high density that appreciable
fusion reactions take over just because

inertia prevents them from separating
themselves just ordinary you know that's

called inertial confinement it's really a
strange name it's not confining at all but

the nurture holds them together
a long long enough for a fusion and

that's the program that
you've probably heard of

the National Ignition Facility
at Livermore the.

I C F program inertial
confinement fusion program

my interests of have always been
in magnetic confinement and

that's the story of which is on this
slide and now you know the sun is

a ball of plasma and you know that
the energy the sun comes from fusion so

I somehow it shouldn't be all that hard
the way the sun manages to confine and

keep the nuclei close enough to each
other to fuse is through gravity

the sun is really really big and it's so
big that the gravitational force provides

the confinement and soon as you see
this fear you know that you've got.

A radio force.

That's holding it together and

that's how the sun manages to
do its job but the reason I

showed this picture is that there's
a little thing there that's not spherical.

Structure there and that structure.

Magnetic confinement that's
a centrally a little dipole field and

eating from one spot and being sucked up
into a neighboring one the little dipole

field lines come out of the sun and
go back in and those lines are lit up and

visible because they're loaded with
plasma and you can see what's happening

the plasma particles are swirling
gyrating around the field

lines they can't get off the field lines
because that's what one part on a charged

particle is in the Merced in the magnetic
field it gyrates around the field lines so

particles and that's really the whole
point of this talk this is this is a token

in the sense this is a magnetic
confinement device right here OK So

you see a big gravitational confinement
device which on Fortunately won't fit

on the surface of the earth and
you see a magnetic confinement device

which might fit on
the surface of the year.

So what's the key to magnetic
confinement now in this picture the blue

lines are supposed to be magnetic field
lines so there's a magnetic field line and

the little red thirty the rebel
red swirl there helix

is a charged particle gyrating around the
field line and you see that that charge

particle can't go marching off out of the
picture because it's trapped on the field

on just as I said right to
gyrate around the field line so

all I have to do is cover that
surface with magnetic field lines and

any particle impinging on that surface
from the inside will be stuck there and

can't get past it because it will have to
do this little dance of this guy's doing.

And so the key to magnetic
confinement is to have a.

As.

A closed surface covered by magnetic field

lines any surface covered by
magnetic field lines it's.

Well the magnetic surface and so
the whole key to magnetic confinement

fusion is a closed magnetic surface.

Now you want to do a little bit
better than just having one so

the idea is to have a sequence of
concentric nested magnetic surfaces

each one inside the other and particles
will have a very hard time getting out.

The will come back to the fact that they
can get out anyway will come back to that

OK but the first thing is OK that now
we know what we need to do we need

to construct a close magnetic surface and
that question comes up

against an interesting point of topology
So here's the so-called magnetic bottle

once again the particle can't
get out of the bottle but

notice that this spiral for example
there's a problem because the field lines

seem to want to meet at the top and
there's no way for them to do that.

There can't be a field and
know they are a place where the magnetic

field vanishes because as soon as the
magnetic field vanishes there's nothing

to keep the particles inside the bottle
there was a stream right out.

So obviously we chose the wrong
way to draw these lines well

let's try a different way I'm not going to
drag this out you see when you do it this

way something funny is going to go wrong
at the top again and at the bottom and

similarly here you can't do it and

this is a famous theorem it's
credited often to prank array and

they can mathematician tell me no
really somebody else did it first but

it's the fixed point theorem Anyway
it says that you can't cover

a surface with a smooth vector field
unless that surface is a tourist.

So that's why all the confinement
devices start to Royal.

And they can't you know it has to be
a real Taurus It can't have any extra

handles on it it has to be top of
logically equivalent to a coffee cup.

So you see there's no problem at all in
a Taurus I could have the field lines

in the short way and that I'm going around
that short way is called Pole loyal and

I'm just telling you that not
that you need to know it but

I'm likely divine mistakes a little later
in the talk because I'm so used to it so

that means going around the short way or
you could also wrap felines around

the long way that's called
toroidal toroidal poloi.

And that is are two
ways easy ways to cover

the donut with I get a clear line to make
a close magnetic surface no problem at all

the way it's done in the token MacTel can
act as you probably know is a Russian word

because it was the first very
successful device of this sort

the way it's a combination of those
two the feel of line here is blue and

it you see that it's polite
a component indicated here in

green and the Troika component so
it turns out for reasons I.

Don't have time to get into.

To do a combination of the two
that's how it's open mike works.

OK So of course I've oversimplified and
here are the main oversimplifications

the particles will bang into each
other every once in a while and

when they do that there's a strong
electric field that breaks this pretty

picture I've been giving and they jump
from one field line to another and

they do that Brownian random walk so
it gives gives rise to diffusion and

it's quick calculation shows that that
diffusion rate is so slow as to be

utterly harmless no problem OK
there was slowly build the fuse but

wait too slowly to interfere with fusion.

You may remember from your in M.
class that when

the magnetic field lines are curved and
particles gyrate around them

in addition to following the field lines
which is their lowest order motion they.

Also drift slowly across
from the field lines and

that turns out to be something that's
easily handled So long story it gives

modestly enhanced losses but
again no problem because in the third but

there really is a problem obviously this
would have been solved a long time ago and

that's fluctuating electric fields often
on substantial length scales are not

tiny microscopic length scale of the truth
fields of much bigger than that.

And they give rise to a more
serious heat lost very serious heat

loss which I'll talk about more later on.

But the punchline of all that
punchline is the right word.

The important point to take home from
all that is you know what With a little

problems they still work tocome X.
actually work.

So here's a picture this is fusion
power produced logarithmic and

this is linear years so you can see
this is a few years old this picture and

these are all devices most of
them in the US there's Alka Torah

which Cristo mentioned the three D.
which he also mentioned T.F.T.

are which achieved.

Something very close to
fusion power out equaling

electric power in and
jet which came even closer.

To the latest you have to write this
to jet is in color one in England and

T F T R's in Princeton and you can
tell the slide was made at Princeton

from the relative positioning of those two
squares I know that call them disputes.

And there's eater there.

And sort of looks like we don't
have all have far to go and

in fact that's my belief either is
designed very much along the line.

Of these two devices and also
the Japanese J T sixty you it's a very

conservative design it tries
to minimize novelty and

just makes things bigger.

OK So so I know what you're supposed to
say yeah it looks like these things work.

On all say that together.

Groups.

There's either.

I hope I have all the participants and
they're the big the big participants I put

them on a separate line or the European
Union or Japan they're paying.

I think thirty per cent apiece.

Since no one in the audience knows
I should have said that with full

confidence.

They're paying a much bigger chunk
then these other people who are paying

ten percent I think it's down to
seven percent of peace now and

the big thing to notice here is that
there's a person you see the person.

There so it's a huge gadget and
if there's time I'll come back and

talk about that hugeness.

OK we're through with the short
course in the future.

And so what's going on in U.S.
fusion research and

this is the simple supposedly
the news part of the tour.

And I think there are four
things going on first and

by far foremost is either there
are a large fraction of the U.S.

investment in fusion research
these days is either related.

And the best way to get your grand funded
if you're doing fusion physics is to

say this is very pertinent to either and

just say that louder than the person
at the neighboring institution.

The third and by the way I don't mean to
denigrate that a lot of very interesting

science is coming out of trying to address
and we'll talk about that a little bit OK.

Looking ahead of eager eater
doesn't look like a very.

Attractive power source.

Who do some historical event but it may
not get the utility industry excited so

let's see if we can find a way to build
something that's much more desirable

cheaper simpler more efficient and
so that's a second thrust

some of that has to do with just what
they call the advanced hokum act making

token Macs work better and some of that
has to do with giving up on the top and

I trying a different screen third
item is a wall interaction mixture of

physics and engineering but not a lot and
a certain amount of pasta physics and

the fourth is fusion power technology
I want to say a few words about each

of the so eager so
first of all it or I don't one so

it has to succeed the program
is over if you're fails.

And as I mentioned the good science
comes out of that desperate need OK so

you should write shouldn't be.

Devalued.

The big things and either and

I'm going to go over this quickly because
I don't think it will mean much to most of

you there are there are things called Age
localized modes or local instabilities

that occur just near the token I favor
the plasma as close to the wall and

they look like they could be very harmful
in a neater environment we've got to

figure out what they're coming what's
making them happen and how to turn them

off there are things called destructions
which we need to understand better.

This is a little bit and tried the second
bullet here alpha particles the ash

D T fusion reactions when that do Kerryman
tritium fuse they form a helium nucleus

helium is a great thing it's
actually in demand it's expensive so

it's great to have your
ASH product expensive but

if until it gets out of the device
it's going to act as a.

Damper on fusion reactions number one and
number two

it there are these are very
fast very high energy.

Particles the alpha particles.

Alpha particles are helium nuclei
they're very energetic and

you have this energetic species in Europe
and it turns out that can be a source of

instability so there's a lot of
people worrying about that and

working on understanding that and the next
bullet is also kind of interesting that

either environment will have
lots of neutrons and that.

Neutrons interact with diagnostics so
these diagnostics the plasma the fusion

program has been using for years all
of a sudden are subject to a bath of

of neutrons and also high energy
particles and and you can't

use the same old diagnostic you've
got to rebuild them redesign them and

in some cases really rethink
them very in a very deep way.

And when you the last item is that you
have a now you have a different nonlinear

system you have a non-linear system where
the heat is supplied by the system itself

and it's at the rate that it wants
to supply heat as opposed to and

at the present time people outside
with their hands on controls knobs and

switches are providing the heat input in

eater that will be out of their
control and the there's a possibility

of new types of nominee your
behavior second of my four topics is

performance enhancement.

Either will operate in
pulses My recollection

is one hundred seconds when I say
my recollection I think you should

take that to mean seventy
five percent confidence.

I think it's a hundred second one
hundred second pulses and then.

I think a minute in between or so it's
going to be like that that's no way for

a come on that's no way for a power source
to act it gets really really hot and

then it cools down for a few minutes and
gets really really hot and

it cools and the thermal stresses
are awful and utility engineers see this

they either laugh or get sick or walk
out of the room or something I think so

people are saying hey we can we can get
around that we can make it up operate in

steady state or
at least very long much longer posts.

Maybe I'll skip the rest of that.

Then you can say well this whole token mac
thing help them actually are great for

making a hot plasma and

she even fusion conditions they have done
that more essentially So they're great for

that but maybe they're not the right
way to make a power generating thing.

And this is really kind of fun
stuff there are ways to make

devices that are intrinsically
steady state no pulsing or

on one hundred second pulse you turn it
on like a fluorescent light just turn on

leave the room OK you can
do that in principle and.

There's another point that gets
me back to this previous slide.

The the there are two parts of
the magnetic field a political part of

the true part it turns out when
you when you study this carefully

you find that all the real confinement.

Is coming from the political part
the toroidal part is there to shrink gyro

radio to make the charity is small and
that don't ask me why I

mean don't we can't don't have time to
get into this makes things more stable so

the Troy will feel which is a huge
investment in dollars big big

bucks in these corals and
putting in their superconducting and

driving hundreds of thousands
of amperes through.

Bux there and
all that's doing is stabilizing things

all the confinement is coming from this
field I'm dragging this out to wrong but

it would be really cool so it looks like a
quality a clue just another word a clue to

looks like a bad design and there are ways
to get rid of the field which people would

love to try I find this a very exciting
part of the program but it's being starved

to death and I mean when I say starved
to death I mean literally to death.

Nowadays.

Plasma wall interaction.

So this is as you can imagine a big deal
I don't know if I want to get into it I

mentioned already the edge logo a lot
localised this is a big effort.

Physics component are fifty percent.

People call it kitchen there's six but

there's some actually some
interesting physics issues in it and

it's a huge thing how does the possum
a come to terms with the wall

if there's time on I may come back and
say.

More about it this last
item is kind of interesting

enough that I didn't have time.

And then I think this is the last
of my four topics maybe I will say.

This is a major topic and it's mostly
engineering but it's kind of exciting

that this is now on the horizon
fusion power so we've got to confront

things that always in the past we thought
were indefinitely postponed but eaters

saying No you've got to think about these
things right now in fact it's probably too

late you should have been thinking
about them for five years already so.

How do you get the alpha particles out the
ash out how good is the how do you design

the system so that the heat being
generated doesn't damage the walls.

Or the.
Those neutrons.

And furthermore tritium
is not something you

trivially find the only way you're going
to happen after trying to keep the fusion

reactor going it's five greeting
pretty and there's a simple reaction.

Where it looks neutron and
lithium gives you tritium and

that that that's no
problem in principle but

and in engineering point if you How are
you going to keep reading that tritium and

you know introducing it into the reactor
This one is sort of seventy five percent

solved maybe getting the power out
you know I get into that can't resist

this last bullet because
it has this great.

Word in it Rami So

when you want to show that you've got real
engineering credentials you just look for

a chance to get the word Rami into
your conversation and you're in.

So that sense reliability availability
maintainability inspect ability.

Rami.

OK What about theory say a few
words about fusion theory.

This is probably more more interest to
insiders but there was a period a very

exciting period in the sixty's before
my time of exploration and innovation.

Tool development what I want to.

Emphasize here is something that
started in the eighty's and

it had mostly to do with
better diagnostics and

interesting story all of
a sudden gradually but

becoming visible in the eighty's there
were diagnostics sophisticated enough and

sensitive enough to
actually test theories and

it was wonderful I mean the effect
on the field was very visible and

very profound and made it made theory
much more fun and exciting and all

of a sudden we I'm serious with physicist
were designing models and making.

And the problem is the fusion
plasmas in these token active

vices were following those predictions
I'm talking about you know five or

ten percent accuracy they were really
doing just what the theory said they would

do sometimes better than five or
ten percent and in fact.

The devices were controlled.

By.
Software that had built into them theories

real theoretical physics fluid
dynamics stuff so it was very cool

what's happening most recently I would
say from about the year two thousand is

an emphasis on large scale simulations
I would say a field day for.

That sort of.

Science.

This is a big saw I'd.

Go over it quickly what is simulation for

it Well traditionally the real
point of simulation was to help you

in the concept of development that's what
theory is really about theory tries to

identify the key points of key concepts
maybe it has to introduce new definitions.

That.

All of which are tools to
understand what's going on and

the traditional goals I think of
simulation were to help in that.

Effort the conceptual development often
using relatively simple models and

but with eater and the cost of
the eater and the importance of eater.

The goal is now very ambitious and
it's to actually predict

the evolution of an eater discharge one
of these hundred second things to predict

what's going to happen putting all the
wall interactions and the plasma physics.

All together.

In a hugely complicated code and

the core of the inner means the interior
part of the plasma and the edge and

this is a big big deal and
I think for people doing it it's a.

Very exciting.

Deal.

I didn't make it to the my two
initiatives and that's good and

there's twenty five minutes left or
even more because I started ten after.

OK.

So I'm going to actually
talk about two specific and

that's there are questions
on the first part specific.

Things that are going on.

Which I find both find interesting
both of which I find interesting so

let me just be the first is a.

Something that I've only been
peripherally involved with and

insufficient Fusion hybrid and
it's politically controversial but

who cares we're just going to
talk about the physics and

the second thing I've been
much more involved in is I so

far more confinement We'll
talk about that OK I'm just so

happy that I got to where I am and
in this time.

So this.

Georgia Tech has a program parallel
to the one of about to describe and

the idea is to say let
me tell you the idea.

The real problem with Fusion the reason
people it's so easy to make jokes about

the fusion program you know it's
always twenty years away or

whatever is that it's first step is so
huge almost every other

technological advance starts out with
a very small thing that kind of works and

that shows that there's a real idea
that when you make a little bit bigger

a little bit better and it develops into
something very important at some point

early in that process industry
catches on gets interested and

invests OK and that's been classic
example is the steam engine

steam engine started out as a device
to pump water out of mines out of

coal mines and board it would collect
in there and waste you know the two.

Areas and they would have a donkey
in the mine going around in a circle

driving a pump to get the water out and
this steam engine was much better

than them than the darky and he didn't
go to the bathroom for one thing OK so

it was a huge improvement and that's
how the steam engine started out and

it was a small step and that's what fusion
has always lacked that first small step

the first step to a fusion is always this
enormous thing you can't make a little

token back OK It just doesn't work because
your diffusion losses will always be.

Fusion OK.

So so it has this huge first step and
it's the whole field

has been third and by the size of that
first step from the beginning and

what's Well I think is cool about this is
that here's an example of a relatively

small first step what you do
is you say yeah it's very hard

to get it's as hard as
you saw ether is big.

To make a power station out of fusion but
it's not hard to make lots of

neutrons out of fusion we can do
that right now lots of neutrons and

you know what neutrons can be very
useful things in particular you can

take the wastes the waste
product of a fission reactor

these are away some of which will last for
thousands of years.

And be very hazardous for thousands
of years you can take those waste and

wash them in a bath of neutrons and guess
what they do that thousands of years.

Nuclear DK In ten years.

OK you wash them in neutrons you can you
can take story I'm Which is not visible

not appropriate for fission reaction
the ordinary isotope of authority and

wash it in neutrons and
produce highly fissionable material and

you can do those things it turns out for
complicated reasons.

And when I say complicated reasons what I
really mean is reasons I never bothered to

figure out you can do all of that
without proliferation dangers and

that is it's a it's a very safe thing
it's something you wouldn't worry about.

Evil people getting ahold of it turns
out to be very easy to control OK so

I mention this quantity Q. which is
the ratio of the fusion power out of

the electric power into the power of
that heat and power in to keep it going.

Either is shooting for Q equals ten.

And will probably make it real workable
powerplant would like to have Q.

equals fifty if you ask and Nero tell you
he will he will say I even think that's

accessible but but that's years off OK
that's years off Q. equals wrong we're

basically there we've done it we've
got Q point seven point eight already.

Done so that's what and that's all you
would ask of this to make this path of

neutrons you don't have superconducting
corals you have copper corals.

And you might change the game for
fission and of course vision is

very unpopular now but this this is an
example of something that can make it more

popular because all of a sudden you
have a solution to the waste problem.

Short of Yucca Mountain.

Those of you know about
the Yucca Mountain Dew that are.

So this is a group my cock
sure thirst white ash Mahajan.

And I want you who have been the main
workers behind this developing this

this is what it looks like there's
the person and it's it's much it's a tiny

fraction of the course I mean
a tiny fraction of the cost of ear.

It's a fusion reactor there it
is right there surrounded by

I'm not actually surrounded by here and
here you can see is a.

Blanket and then through that
blanket you would either put.

Vision waste but you're not going to get.

The toxified What is the word I want
they're going to get pushed down to.

Relatively harmless levels or third floor
in which you're going to turn into this

simple material and there's a very simple
way you can remove the fusion core and

replace it when you need to
service things to replace it.

And I hope I said that there's
a competing similarly motivated proposal

coming from Georgia Tech come your
nuclear engineering department I think.

Now here's either again and there's
this gadget that I'm talking about so

you see the scale size.

The difference in scale and
there's an even bigger difference in cost

and it's.

Based on technologies already
underdeveloped and it's tries to be very

simple and straightforward in operation.

There is a.

There is one piece of physics here that's
interesting I mean just take a moment

to talk about.

That's my culture it's there by the way.

Why didn't people for
a long time ago say hey let's make.

A Q. equals one small token back just for
fun just as for example

university experiment and the reason is
that if you're really going to get to Q.

equals one that means you're
producing lots of fusion power.

And something this small you're
going to have a huge amount of heat

the neutrons can you know you
can shield the neutrons but

the heat a huge amount of heat is
going to be impinging on this wall and

the wall will simply corrode erode
away from this enormous heat load.

All token Max nowadays in order to
control ash removeable and to have

a knob to control how much plasma is in
the machine what's called the diverter and

what you do is you take the outer
field lines they're in pink here and

you divert them so
that the outer ones instead of being and

closing the plasma go off
in a new direction and

hit a metal plate and.

You see that happening this looks
conventional here I'll tell you what's

new about it in a minute but so far this
could be just a conventional what's called

a diverter diverter is a little plate you
extract from fear lines the outermost

class after the plasma has diffused across
this separate checks it follows these

outer feeder lines and hits that plate
you've concentrated all the heat load

in that area which is means
that you protected the wall and

you've also gained control over over the
plaza but of course what's going to happen

to that plate and the answer is this if
this were a conventional diverter and

this device was producing equals
one that much fusion plate

would be vaporized OK And
you'd be in bed trouble and what.

My country ruther and

his colleagues there's a big
idea there's a very clever way.

Which would be take we explain to spread

these field lines these felines are not
just going the way they say they're also

moving in the third dimension
the troika way all the way around and

that's done in a very subtle clever way so
that by the time and

during that whole long trip
that the postman makes

royally on those field lines it's
radiatively cooling it's radiating like

mad and cyclotron radiation and
getting colder and colder to.

By the time it hits
the plate it's an accuracy.

That's the big idea it's a single
technical idea very difficult but

they've done it and there's no
question that they've done it and

that's what makes a small such
a small scale on reactor possible

I guess I've said all that here.

When I say they've done it they have only
done it numerically by simulation but

it's been sufficiently
convincing that the major new

mac at column laboratory in England
is installing Mr Berger and

in fact the community as more of
us acknowledge that this will work

I personally have no doubt about it at all
it's were based on very simple physics

it's a complicated design but
this basic idea is very simple and so.

There's very little question
about the viability of this and

as I said it's being installed at
column I think the time scale for

that to be seen is less than a year now.

OK So I think I've said most
of this you reduce the volume.

Of nuclear waste you don't
have to build one of these for

every fission reactor for
every twenty Vision reactors you

have one of these gadgets
the compact neutron source.

And you could also I said do.

Fuel breeding and
I haven't you're trusting me on this or

maybe you're not but there's a long
complicated argument that shows that and

with regard to the proliferation
this is very safe very

attractive from that point of view.

But that's the end of that
story is coming to my second.

Physics topic and my last topic anyway
that's the the compact neutron source.

OK So there's a long tradition
in the field to fusion physics

saying that we can't do thermodynamics of
course because these are systems far from

equilibrium and thermodynamics only
pertains to equilibrium systems so

if you're going to study.

And and magnetic and time and forget about
equilibrium the story goes on to say

in the equilibrium state everything is
happening the diffusion has taken place

and all the gradients are smoothed out and

this wonderful confined plasma has
spread itself over the universe.

So that's the standard.

Dogma and people believe that sounds
kind of plausible I guess and

with the result that there's
almost no permanent damage in.

Physics and magnetic communion physics.

But it's wrong OK it's wrong I
mean it's true that eventually.

If you go to the longest possible
time scale you know all the neutrons

will it be Kate away or or
whatever OK the thermodynamics says and

say there's some holy thing called an
equilibrium state and we know exactly what

it is all thermodynamics says is that
there are things that happen fact

that there are some things that
happen faster than others.

When the fast things are mixing
from the first things are mixing

then on a slower time scale we will see
a mixed system a mixed system means

a system that has found
its most probable state.

And as soon as the system
find its most probable state

in the thermodynamical crank everything
works perfectly and all you required for

that is a separation of time
scales a fast thing that mixes and

a slower thing which is
a time scale of interest.

Going in a mix and there's never
an equilibrium state in any absolute sense

but put a glass of water on the table.

OK And we all see the say well the water
is going to evaporate until the vapor

pressure exists in the dogma that's it but
eventually you're not waiting long enough

if you wait long enough
the glass evaporates.

But that's a much slower time scale and
exactly.

The reason thermodynamics works is because
the separation of time scales OK I'm I'm

going on too long about that so
that's the slight.

But as a result of this solely prejudice.

We haven't been taking advantage of
very powerful methods of physics so

let's look for an equilibrium distribution
in this sense it is on the sense that

there's a fast thing and we're looking for
things that occur much more slowly by

the way that separation of time
scales is absolutely common.

Base of in fusion science separate
things that are much faster and

things are not that's why the fusion
simulation program and start challenging

separation of time scales is great if
you're an analytical theorists and

it's a nightmare if you're
a numerical scientist.

Separation times goes very common so
I'm getting into stuff here which

was started by Peter Cato a friend
of mine and collaborator on this so

I want to make sure I mention his
name right away so I write down.

Kinetic equation familiar to some of you
have done the will kinetic theory for

distribution function which on some
slower time scale is changing slowly so

there's no D.F.T. T. term and on the right
hand side it's a collision OPERATOR And

you can take the went out collision
operator whatever your favorite collision

operator is.

Both face P. is the momentum and is the.

Relativistic energy and what.

Peter Cato did was to say is there
an interesting solution that's confined

that's confined and
which both sides of this equation vanish.

If the right hand side vanishes collision
only equilibrium has just means

that it's as messy as it can be
collisions can make it any messier and

if a left hand side vanishes
it's a kinetic equilibrium and

I spelled equilibrium wrong both times and

no one has ever given a talk with slides
without misspelling something but

I thought I was going to be that.

OK So to be a collision of equilibrium
you have to be a little Lawrence scalar

depending only on collision and variance.

And in the local fluid rest rain
you have to be an actual Boltzmann.

I'm counting on your having some
course of making those statements

and there it is where the beautiful
thing here capital you there it is

capital you is the four vector
velocity fluid velocity

not the microscopic the fluid velocity.

Little Piggy is the microscopic prosody
the actual velocity of a particle and

this capital D. is the fluid velocity and
and capital P. is the canonical

momentum the combination of
the ordinary months and the.

DOCTOR potential together here.

And right.

If you go to the rest frame you
see that this is exactly a Maxwell

in the rest frame that's capital U.
is just one the D.

is zero so all you get is the zero
component of capital T. and

that's just the plus the zero component of
that which is the electrostatic potential

that is exactly
a Maxwell Boltzmann distribute.

So Peter had a smart idea.

He wrote it very differently Well
that's why I don't go into any

more details than that.

OK Well Peter Knight went through the and
some details and by the way it's not quite

as wonderful as I'm saying but let's let's
pretend it is it's more fun to camp but

it's close to his wonderful
is what I'm saying OK so.

She really.

Here we are OK So there's a little
mix up there but it's not important.

This is.

OK let me just see if there's more.

It's OK so so as I said we went through.

When you go through this yeah I can
do it from here this is cool so

you noticed that when you do this you
find that in the restaurant this is

a Maxwellian but in the lab frame
in the frame of the system of

the confining system
it's got this philosophy.

And it's easy to calculate
the velocity v and

that's what this later slide shows.

And that's what it turns out to be zeta
is the toroidal going all the angle

going around the long way so
what turns out it turns out that this.

That we've constructed have
these wonderful properties.

And this is where the kinetic equilibrium
to I'm sorry so I told you that it had to

be a drifting Maxwellian to be a collision
only equilibrium to be kinetic only

equilibrium what you find is the velocity
must be precisely that philosophy and

what it is it's velocity so
the donut is rotating about its vertical

axis the whole plasma is
rotating not quite rigidly this

well rigidly in a sense this capital R.
is the major radius the distance from the.

Center of the donor

outwards.

Here's the down and
here's the center of the donut and R..

Is that distance.

And you find that if the rotation rate
if he is given by that expression

where the rotation rate is given
by this expression I guess

the hope the notation to N. is the density
five is the electrostatic potential if

that's true then.

I do mention Peter K. a good for
me then indeed you find out that

the distribution makes the left hand
side of the equation vanish also it's

an exact kinetic equilibrium so we have an
exact solution and so we mark of zero so

unusual implies a physics and
exact solution to a kinetic equation and

it's quite simple it has to
rotate at a prescribed rate.

And we're where there.

Then you ask is it confined.

To be confined it has to have zero
density at some finite radius or

at least exponentially small
radius this is the paper Peter and

I wrote together about
this what a long time ago.

We get in these things never real tokamak

Plasmas do spin toroidal e not a precise
they are alot of you but they do

spin shortly I'll tell you why they're not
approach shots they are velocity and but

they're never relativistic in
effort to vote Asians we do much

like to be Rhoda So we did a.

Non-relativistic limit and what you find.

It's an insurer.

Calculation in requiring Kweisi
neutrality that the local

density be the same as the local
electron density is that the density

varies in this way.

Maybe this is getting
a little bit complicated for

me to explain in detail but
there is one point here this is

first time it's appeared on
Fortunately side is the Poil flux and

it's a measure of radius so I think of.

It's an exact thing but
it's Think of it as a measure of not this

radius.

But that radius the radius from the.

Inside the radius in
the plural cross-section.

And the whole point of this.

Expression is that the density
becomes exponentially small as Psion

creases So there's an exponential
fall off of the density with

a minor radius.

I want to go back to the slide now.

And just for just for this picture and

here's the picture that yeah.

It's significant Yeah.

Sorry I'm a little bit what's significant.

Yes.

Is the absence of
a temperature gradient here.

And OK Now usually the temperature
gradient is a great big thing after all

at the wall the plasma supposed to have
some temperature close to that of the wall

temperature in the center it's supposed
to be one hundred million degrees OK so

the temperature gradient is a huge.

Thing.

It's in easy observation and

it's because of that huge
temperature gradient that all.

Are turbulent and
unstable OK it's exactly putting a pot of

water on the stove not exactly.

You're just generating so
much heat that the and

we requiring imposing such
a steep temperature gradient

that the heat has to get out
through turbulent convection.

If this is observed in the sun the sun
he conduction in the sun is largely from

turbulent conduction and for the similar
reasons there's no temperature gradient

here this gadget has a flat temperature
profile that's what we call it I still

thermal It has a five temperature profile
and you would say that's ridiculous that

means that the you're asking this wall to
withstand one hundred million degrees but

I hope you see the point.

If I can find the point the point is that
by the time you get to the wall there's no

density left yes the temperature
is still very high it should

be in theory it's absolutely flat out tell
you why I gave it a little curvature here

but but there's no density
there's no plasma there.

There's exponentially
little plasma there OK so

you can have a flat temperature profile.

If you have a sufficiently deep density
profile Exactly and that's the that's

the cool thing about this I mean the
question about this is this have anything

to do with the real world and that's still
a question but I tend to think it does and

I'll tell you why and it tells us that
we were all along making a mistake to

thinking we had to bring the temperature
down before you reach the wall you don't

have to bring the temperature down before
you reach the wall if the density is

already very well so that's part of what
come out comes out of this OK if back.

It was so here this summarizes
what we thought I found.

There's a unique you can't there's
very few free parameters once you say

that you must have like both the kinetic
equilibrium and a collusion an equilibrium

everything else is fixed it turns out that
what's really coming out is that you have

to have constant chemical potential I
won't go there though and so would I So

it's I still thermal confinement based on
an exponentially reduced wall content.

And then here's the last point.

Good that I that I was in this regard that
I want to bring up there is a gadget.

Following this theory I printed L.T.
X. and

it has an additional property of a lithium
liner let's not talk about that but

it has a nearly flat temperature profile
and in fact its temperature profile looks

like the one in that slide I showed you
a minute ago just at the very end occurs

on a little bit that's why I used
that because that's where the L.T.

X. looks like so this is been done and
guess what it's very stable and

has remarkably good confinement
properties it's small and

it's under-diagnosed because nobody can
afford to buy diagnostics for it and

it may even now have been terminated
because eater Smalling everything up

but there's no question about this
there's lots of lots of data on L.T.

X. and L.T. X. looks a lot like
what I've been telling you so

that there's reason to think this is
all real OK So this is my summary

slide.

The US fusion reef search program really
is very different from what it was five or

so years ago there's an eager
focus which is exciting and

stimulating forces us to
look at hard questions

some of which turn out to be very
interesting but it's also constraining.

And it's hurting other parts of the
program and involves a mix of science and

technology not all of which is aimed at
either but it is looking beyond eater and.

I hope the two physics ideas I showed you.

Make the point that exploration and
innovation are still important parts

of the fusion programme and which
continues to thrive on creative thinking

I think that's probably my last slide
it is indeed thank you so much for your

attention.

OK so the name is still beguiled
some people believe what

the metal of choice now is or
stand out exterior and

don't ask me to go expand on that
that's correct yes arsenic still has

it has its sufficiently robust for
this yes.

Yes So.

You are supposed to come on line and I
have in my slide it said two thousand and

twenty that came from a car from somebody
I know who is involved I recently saw

a need or publication that said Twenty
nine hundred that's for turning it on.

And what Crystal said was accurate it's

been postponed several times the cost
is increased by several factors.

I will say that it my information.

Mation is that it's more on
track now than it used to be and

maybe we're not going to see another and
in cost increase.

It's what I'm to been told.

Yes.

You know it was.

A good question so we're not you know
ASCO or any existing organization it was.

What was called the eater council and
they had many meetings some of which

were quite bitter and but they were just
people in the U.S. fusion who got the U.S.

representative was at that time
deputy secretary secretary of energy.

And a good question so it was a less
formal thing than what you're

describing just people getting together
and ironing out these agreements and

then not an easy process.

Yeah.

Let's let's look at the sure.

Maybe this is the slow
yes it must be right.

This is a very technical thing but
it's actually quite scary.

Localized modes and general stability of
it are the point is we there are things

called disruptions for example which occur
on present day devices and so what but

eater would be an electromagnetic
pulse of serious proportions and

so either is designed to only take I
don't know three destructions a year or

something some finite number and
we better make sure we

know exactly how to avoid them I'm sort of
agreeing with you but I'm saying that this

one that might look relatively harmless
It's not at all harmless the second

that I think is less scary for
me I that's where the diverter does it and

everybody seems like it will work.

I don't know.

This is just money here I think just have
to put I have to redesign diagnostics but

if that's just money and you know I'm
the usual good technological thinking.

Know what to say about this last
item except I expected to be kind of

interesting no I don't see any of these.

Things.

That's right you're absolutely right
to say that I don't want to sound

overconfident but people have
thought about that for so long and

done so much work on that and
they simply say yes well and

they simply say yes we
can handle the heat load.

And and the reason I believe that is
that eater could turn up its parameters

considerably good you bet raise this point
it could look much sexier in terms of

Q. except that they can accept
the heat load so it's the dealing with

the heat load that has nailed them
I can recall Sten I think it's ten.

They could out.

Because they they don't have
confidence in their ability to deal

with the heat load of a higher level so
that's a constraint.

But I think it's something that's pretty
well understood I don't think there's

a lot of mystery to it whereas these
guys much less well understood.

Yes.

It would definitely be.

A.
Token amount compared to the initial

Yes I think we have this
discussion I had so

many discussions today forgot to whom
I said what So the I'm going to say

something bad about.

Inertial confinement fusion Now first of
all inertial confront a fusion has three

motivations number one is defense we can
talk about that sometime if you want or

now if you want but number one has a big
defense thing it was based on the basis of

national defense that it was
originally funded number two simulating

in the laboratory at the at the site
astrophysical conditions and

interiors of stars collecting Jets
things like that can be simulated

at these very high energies that the
National Ignition Facility will produce

And number three fusion energy and
I can't comment on the first of

those objectives I think the second one is
reasonably plausible of all expensive but

plausible and the third one I
don't think it's plausible and

the reason I don't think I have that
feeling about the energy application.

Is that is this you have a little capsule

you hit it with ninety six
light lasers it implodes and

indeed it pop it going to explode like
it's a fusion firecracker so it's a.

Firecracker size hydrogen bomb.

The amount of energy electrical energy.

Electrical energy you get from that pop

is thirty five cents is worth
thirty five cents on the market.

OK so you have to make this caps on if
you know about the capsules but they

have multiple layers they have plastics
and they had high using materials and

they had to tearing which are all
in the layers inside this sphere.

You've got a pop and
you've got to build it.

Clean out the ash left over very
important to the next one pop and

you've got to do all that for thirty five
for less than thirty five cents a pop.

And of story.

So but
in terms of achieving Q equals one or

Q equals five or
whatever it's likely that and

I that the National Commission facility
will win that and that's great.

Because But but in terms of making a
reactor you'll be asked about a reactor on

the grid that will power the grid
I I don't I don't see that.

Because of what I just said.

Is.

There.

Just.

I think the real field exciting field for
theoretical Pozen physics.

Now.

Is astrophysics but but there are foreign
challenges and in fusion physics

Well the sort of on the slide I would say
would be really exciting to figure out.

These things and
also the possible wall interaction which.

Is sort of here.

So there are exciting challenges and
infusion but

in terms of positives six I would
say the most fun appealing.

Just lie in posture astrophysics.

I think that most of the the most
interesting things we see

in in the astrophysical world have
a central plasma physics component and

I think that they could be treated
by this if instigated methods

developed in the fusion program much
better than the way they're being treated

now.

Thank you.