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T h e P l a s m a S c i e n c e & F u s i o n C e n t e r M a s s a c h u s e t t s I n s t i t u t e o f T e ch n o l o g y
Understanding the basic physics o plasmas is necessary not only to advance usion research, but to increase
the physics-based oundations o plasma-related scientifc disciplinesand applications.
Members o the Physics Re-
search Division, including
theoretical and experimen-
tal plasma physicists, aculty mem-
bers, graduate and undergraduatestudents and visiting collaborators,
work together to better understand
plasmas and to extend their uses.
Theoretical Plasma PhysicsUsing the undamental laws o
physics, theorists at the PSFC are
developing improved analytical and
numerical models to better describe
plasma phenomena both in the
laboratory and in nature. Teoreti-
cal plasma research is essential not
only to better understand basic
plasma physics, but also to sup-
port many areas o usion physics.
In addition to basic plasma theory,
topics being pursued at the PSFC
include tokamak research on radio
requency heating and current drive,
core and edge transport and turbu-
lence, and magnetohydrodynamic and
kinetic stability. Tis research sup-
ports the PSFC tokamak, Alcator C-
Mod, and the Levitated Dipole Experi-ment (LDX), as well as other such
experiments around the world.
Interaction between MI research
sta and scientists at other acilities
osters vital scientic collaborations in
the US and abroad.
MI Teorists also investigate concepts
to improve tokamak perormance. One
promising approach to advanced
tokamak operation uses radio requency
waves to control pressure and current
proles in order to control instabilities
and achieve steady state operation in
high pressure plasmas.
In the area o inertial connement
usion (ICF), theorists study the
ablation process, during which a
plasma is created that causes nonlin-ear scattering o the laser light. Tis
scattering not only reduces how
eciently the target can be heated, but
also generates hot electrons that can
preheat the core, inhibiting compres-
sion. PSFC theorists ocus on under-
standing experimental observations o
scattered light due to laser-plasma
interactions, hoping to nd ways to
control the deleterious eects o these
phenomena.
Ph
otobyPaulRivenberg
Dr. Jan Egedal works atop the Versatile Toroidal Facility, a medium-sized tokamak currently
used to study magetic reconnection, a phenomenon observed in solar ares.
Research includes:
Laboratory experiments
Development o novel
plasma diagnostics
Theory o magnetically
confned usion plasmas
Nonlinear wave
propagation, turbulence
and chaos
Space plasma physics
Plasma astrophysics
Laser-plasma interactions
Physics ReseaRch
T h e P l a s m a s c i e n c e & F u s i o n c e n T e r m a s s a c h u s e T T s i n s T i T u T e o F T e c h n o l o g y
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Experimental Plasma PhysicsExperiments are conducted both on-
site at the PSFC, on small-to-medium-
scale experimental devices, and o-
site, on large-scale national and
international usion devices.
Levitated Dipole Experiment
Physicists at the PSFC are exploringnovel magnetic connement congu-
rations that are undamentally di-
erent rom the tokamak. Tese may
lead to alternate reactor concepts,
and provide insights into space and
astrophysical processes. One such
approach, which uses a levitated cur-
rent-carrying superconducting ring,
is being pursued as a collaboration
with Columbia University. Such a
current ring generates a dipole type
magnetic eld geometry, which in turnconnes a torus o hot plasma. Dipole
connement is observed in nature to
be robust (e.g., in the magnetosphere
around the planet Jupiter). Tis Levi-
tated Dipole Experiment (LDX) will
improve our understanding o dipole
connement in a laboratory setting.
Experiments include:
exploring new
confnement concepts,
such as the Levitated
Dipole Experiment;
developing new
diagnostics or measuring
plasma parameters;
investigating space
physics phenomenathrough laboratory
simulations and o-site
ionospheric observations;
developing novel
diagnostics or inertial
confnement (ICF)
physics experiments;
exploring novel scientifc
uses o plasma phenomena.
DOE Ofce o Fusion Energy Director o Research John Willis and MIT Associate Provost Alice
Gast cut the ribbon or the Levitated Dipole Experiment, joined by members o the LDX team.
Graduate students working on the project sit atop the vacuum chamber.
Nuclear Engineering Proessor Jerey Freidberg
(above let), Associate Director o the PSFC,
teaches plasma physics-related courses and
supervises student theses.
Many theorists work with
graduate students on
cutting edge research.
Dr. Peter Catto advises
Natalia Krasheninnikova,
who is studying plasma
stability. Some o Dr.
Cattos research ocuses
on how the electric feld
is established in both the
edge and core o toka-
maks like Alcator C-Mod,
MITs premier
usion experiment.
PhotobyMPMcNally
Dr. Abhay Ram combines teaching with
research in the areas o plasma heating and
current generation by radio requency waves,
nonlinear plasma dynamics, space plasma
physics, and laser-plasma interactions.
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Phase Contrast Imaging on
DIII-D and C-Mod
It is now widely believed that micro-
turbulence in magnetically conned
usion plasmas results in excessive loss
o particles and heat. o better under-
stand such turbulence, PSFC research-
ers have developed a new diagnosticusing CO
2lasers and a special imaging
technique widely used in microscopy
- phase contrast imaging. Tis diagnos-
tic, which provides detailed measure-
ments o the density fuctuations with
extraordinary sensitivity and ne
spatial and temporal resolution, is
being used to study turbulence and
RF waves on the DIII-D tokamak in
San Diego, and on the Alcator C-Mod
tokamak at the PSFC. Recent up-
grades will allow tests o some o thelatest theoretical predictions regard-
ing the stabilization o microturbu-
lence, leading to improved conne-
ment and RF wave propagation.
Magnetic Reconnection
Research sta and students investigate
magnetic reconnection using the
Versatile oroidal Facility (VF), a
toroidal acility built largely by
graduate and undergraduate students
and PSFC sta. Magnetic reconnec-
tion is the breaking and reconnecting
o magnetic eld lines interacting with
plasma. Reconnection controls the
spatial and temporal evolution o
explosive plasma phenomena such as
solar fares, coronal
mass ejections and
internal disruptions
in magnetic usion devices. VF has
made it possible to measure the
plasma response to reconnection with
unprecedented accuracy in the
laboratory, stimulating the develop-
ment o new theoretical models or
reconnection.
Joint European Torus (JET)
Tis program conducts collaborative
experiments at the Joint European
orus (JE) in England, the world's
largest tokamak and the major
experimental tool o the European
Fusion Development Agreement. In
MIT undergraduates work with the All Sky Imaging System (ASIS) designed to diagnose plasma
turbulence occuring in space and laboratory plasmas. ASIS can record inrared, visible, and ultra-violet emissions to determine the profles o plasmas and the structures o plasma turbulence.
JET, in England, is the
largest tokamak in the
world, and is improving
understanding o plasma
stability and transport.
these experiments researchers study
instabilities driven by high-energy
particles, such as radio requency-
driven energetic ions and usion-gen-
erated alpha-particles. Tese studies
lead to an improved understanding
o plasma stability and transport that
will be important in a burning plasma
experiment such as the internationalcollaboration IER, where the u-
sion process generates a substantial
alpha-particle component. Te results
o our research have claried the
relation between these waves and the
plasma to such a point that inorma-
tion about some o the plasma's most
important parameters can be ob-
tained rom the wave measurements.
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Plasma Science & Fusion Center 77 Masssachuset ts Ave., Cambridge, MA 02139 Ph: 617.253.8100 Fax: 617.253.0570 [email protected] ww w,psc.mit.edu/
Ionospheric Plasma Research
Researchers and students in this
program perorm eld and laboratory
experiments to understand plasma
turbulence due to radio requency
heating. Tey travel to Alaska, PuertoRico and other sites or their investi-
gations. Students use the Ionospheric
Radar Integrated System (IRIS) at
Millstone Hill, Massachusetts, or
remote sensing o space plasma turbu-
lence, and the All Sky Imaging System
(ASIS), to study the spatial structures
o this turbulence. Understanding
turbulence will aid satellite communi-
cations, and will help control plasma
turbulence in uture usion devices.
Laser-Plasma Interaction
Te Division is collaborating with the
University o Rochester Laboratory or
Laser Energetics (LLE) and theLawrence Livermore National Labora-
tory (LLNL). Tis eort is designed to
provide extensive diagnostic inorma-
tion about Inertial Connement
Fusion (ICF) plasmas by making
spectral, spatial, and temporal
measurements o charged usion
products with novel instrumentation.
Current experiments on the OMEGAlaser acility at LLE have provided
inormation about usion yield, plasma
temperature and density, implosion
symmetry, implosion dynamics, burn
symmetry, stopping power o hot
plasmas, and laser-plasma interactions.
National Ignition Facility
PSFC scientists are also active in den-
ing the science that can be studied at
the uture National Ignition Facility
(NIF) at LLNL. Tis $2.1 billion acility
will ultimately be the center or inertial
usion research in the US. NIF will
oer unique opportunities to explore
the properties o matter under extreme
pressures (~500 billion atmospheres)
and densities (~1000 g/cm3). PSFC
One o the noveldiagnostics PSFCscientists have developed
or the National Ignition
Facility (NIF) would use 31
MeV protons, generated
within the NIF capsule, to
help scientists determinewhether NIF has achieved
its goal o producing
substantial themonuclear
gain during pellet implosion.
PhotocourtesyofLLE
PSFC Group Leader Richard Petrasso (bottom right) looks on as the MIT-designed
charged particle spectrometer (upper right) is installed on the target OMEGA laser at
the University o Rochester Laboratory or Laser Energetics (LLE) .
scientists have developed two novel di-
agnostics or NIF that could be used inaddition to many o the charged-par-
ticle diagnostics they have developed
or OMEGA. Te rst new diagnostic
would use 31-MeV protons, gener-
ated within the NIF capsule, to help
scientists determine whether NIF has
achieved its goal o producing substan
tial thermonuclear gain during pellet
implosion. Te second new diagnostic
would measure the energy spectra o
usion neutrons that are downscat-
tered by the compressed capsules, to
determine the amount and symmetry
o capsule compression. Because this
diagnostic has a wide dynamic range i
will be useul during all stages o NIF
development, rom low-yield initial
experiments to high-yield ignition.
T h e P l a s m a s c i e n c e & F u s i o n c e n T e r m a s s a c h u s e T T s i n s T i T u T e o F T e c h n o l o g y