G A-A22258
ROTATIONAL AND MAGNETIC SHEAR
STABILIZATION
OF
MAGNETOHYDRODYNAMIC
PERFORMANCE DISCHARGES
MODES AND TURBULENCE IN DIN-D
HIGH
by
L.L.
LAO, K.H. BURRELL, T.S. CASPER, V.S. CHAN,
M.S.
CHU, J.C. DeBOO, E.J. DOYLE,
R.D.
DURST,
C.B. FOREST, C.M. GREENFIELD, R.J. GROEBNER, F.L. HINTON,
G.A. NAVRITIL, T.H. OSBORNE,
Q.
PENG, C.L. RETTIG, G. REWOLDT, T.L. RHODES,
B.W.
RICE,
D.P. SCHISSEL,
B.W.
STALLARD, E.J. STRAIT, W.M. TANG, T.S. TAYLOR,
A.D. TURNBULL, R.E. WALTZ,
and
The DIN-D TEAM
Y. KAWANO, E.A. LAZARUS, Y.R. LIN-LIU, M.E. MAUEL, W.H. MEYER, R.L. MILLER,
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United States
Government. Neither the United States Government
nor
any agency thereof, nor any of their
employees, makes any warranty, express
or
implied,
or
assumes any legal liability
or
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bility for the accuracy, completeness, or usefulness
of
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or
process
disclosed,
or
represents
that
its use would
not
infringe privately owned rights. Refer-
ence herein to any specific commercial product,
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or
service by trade name, trademark,
,
manufacturer,
or
otherwise does not necessarily constitute or imply
its
endorsement, recom-
mendation,
or
favoring by the United States Government
or
any agency thereof. The views
and opinions
of
authors expressed herein do not necessarily state
or
reflect those of the
United States Government
or
any agency thereof.
AUGUST
1996
GENERAL
ATOMRCS
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United
States Government. Neither the United States Government nor any agency thereof, nor
any of their employees, makes any warranty, express
or
implied, or assumes any legal
liability
or
responsibility for the accuracy, completeness, or usefulness of any information,
apparatus, product,
or
process disclosed,
or
represents that its use would not infringe
privately owned rights. Reference herein to any specific commercial product, process,
or service
by
trade name, trademark, manufacturer, or otherwise, does not necessarily
constitute or imply its endorsement, recommendation, or favoring by the United States
Government or any agency thereof. The views and opinions of authors expressed herein
do not necessarily state or reflect those of the United States Government or any agency
thereof.
DISCLAIMER
Portions
of
this
document
may
be illegible
in
electronic image products.
Images
are
produced
from
the
best
available
original
document.
GA-A22258
ROTATIONAL AND MAGNETIC SHEAR
STABILIZATION
OF
MAGNETOHYDRODYNAMIC
PERFORMANCE DISCHARGES
MODES AND TURBULENCE IN DIII-D HIGH
bY
DOYLE,~ R.D. DURST,~
C.B.
FOREST,
C.M.
GREENFIELD,
R.J.
GROEBNER,
F.L.
HINTON,
Y.
KAWANO,~
E.A. LAZARUS?
Y.R.
LIN-LIU,
M.E.
MAUEL:
W.H.
MEYER,*
R.L.
MILLER,
G.A.
NAVRITIL!
T.H.
OSBORNE,
Q.
PENG,
C.L.
RETTIG,~
G.
REWOLDT?
T.L.
RHODES,~
B.W.
RICE,*
D.P.
SCHISSEL,
B.W.
STALLARD,*
E.J.
STRAIT,
W.M.
TANG?
L.L.
LAO,
K.H.
BURRELL, T.S. CASPER,*
V.S.
CHAN, M.S. CHU, J.C. DeBOO, E.J.
T.S. TAYLOR,
AD.
TURNBULL, R.E. WALTZ, and The DIII-D TEAM
This is a preprint of an invited paper to be presented at the Thirty-
Seventh American Physical Society Annual Meeting, Division of
Plasma Physics, November 6-10, 1995, Louisville, Kentucky and to
be published
in
Phys.
Plasmas.
*Lawrence Livermore National Laboratory, Livermore, California.
tuniversity of California, Los Angeles, California.
*University
of
Wisconsin, Madison, Wisconsin.
§Japan Atomic Energy Research Institute, Ibaraki-ken, Japan.
YOak Ridge National Laboratory, Oak Ridge, Tennessee.
'Columbia University, New York, New York.
'Princeton Plasma Physics Laboratory, Princeton, New Jersey.
Work supported
by
the
U.S. Department
of
Energy
under Contract Nos. DE-AC03-89ER51114, W-7405-ENG-48,
DE-AC05-840R21400, and Grant
Nos.
DE-FG02-89ER53297 and DE-FG03-86ER53266
GA
PROJECT
3466
AUGUST
1996
GENE-L
ATOMICS
L
L.
Lao,
et
al.
ROTATIONAL AND MAGNETIC SHEAR STABILIZATION OF MAGNETOHYDRODYNAMIC
MODES AND TURBULENCE
IN
DIII-D
HIGH PERFORMANCE DISCHARGES
ABSTRACT
The confinement and the stability properties
of
the
DIII-D tokamak [Plasma Phys. and
Contrl. Nucl. Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987),
Vol. 1, p. 1591 high performance discharges are evaluated
in
terms of rotational and magnetic
shear with emphasis on the recent experimental results obtained from the negative central mag-
netic shear (NCS) experiments.
In
NCS discharges, a core transport barrier is often observed
to
form inside the NCS region accompanied by a reduction
in
core fluctuation amplitudes.
Increasing negative magnetic shear contributes to the formation of this core transport barrier, but
by itself is
not
sufficient to fully stabilize the toroidal drift mode (trapped-electron-qi mode) to
explain this formation. Comparison of the Doppler shift shear rate to the growth rate of the
qi
mode suggests that the large core
EXB
flow
shear can stabilize this mode and broaden the region
of reduced core transport
.
Ideal and resistive stability analysis indicates the performance of
NCS discharges with strongly peaked pressure profiles
is
limited by the resistive interchange
mode to low
PN
I
2.3.
This mode is insensitive to the details of the rotational and the magnetic
shear profiles.
A
new class of discharges which has a broad region
of
weak or slightly negative
magnetic shear (WNS) is described. The
WNS
discharges have broader pressure profiles
and higher
p
values than the NCS discharges together with high confinement and high fusion
reactivity.
GENERAL ATOMICS REPORT GA-A22258
iii