Resistive MHD Stability Analysis and High Normalized Beta Plasmas Exceeding the Ideal Stability Limit in KSTAR by YS Park Columbia University USA KSTAR Hmode equilibria have reached the n 1 ideal MHD nowall stability limit computed with Hmode profiles ID: 783627
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EX/P8-05 : Plasma Rotation Alteration by Non-axisymmetric Magnetic Fields, Resistive MHD Stability Analysis, and High Normalized Beta Plasmas Exceeding the Ideal Stability Limit in KSTAR (by Y.S. Park, Columbia University, USA)
KSTAR H-mode equilibria have reached the n = 1 ideal MHD no-wall stability limit computed with H-mode profilesHigh values of bN up to 2.8 with li of 0.7, bN /li > 4Plasma rotation has been significantly altered with n = 2 applied 3D field from the device in-vessel control coil (IVCC)By utilizing middle IVCC only, ~60% reduction in core rotation achievedFull scans made for control techniques utilizing different n = 2 spectra, and supersonic molecular beam injection which showed distinctive effectsMeasured non-resonant NTV strength ā dB2, Ti2.27, which follows the collisionless regime scalingResistive stability analysis in KSTAR plasmasMeasured 2/1 tearing mode stability is compared to Dā computed from the PEST3 Full resistive MHD solutions from M3D-C1 shows a qualitative agreement with the PEST3 The effect of sheared toroidal rotation is found to be strongly stabilizing from the M3D-C1 results
b
N
/li = 4
bN /li = 3.6
n = 1 with-wall limit
n = 1 no-wall limit
First
H-mode(2010)
Previous max. bN(2011)
Recent
operation(2012)
Y.S. Park, et al., PoP 21 (2014) 012513
KSTAR 8062 CES
Rotation reduction
KSTAR equilibrium operating space exceeding the ideal stability limit
With n = 2 applied field
Plasma rotation profile reduction by the applied n = 2 field
The radial velocity
eigenfunction
of a 2/1 tearing mode stabilized by a sheared rotation from M3D-C
1
A
B
C