Abstract
The multi-fieldmulti-scale core ( ∼ 0.5-0.8) turbulence response to electron cyclotron heating (ECH) of DIII-D Ohmic plasmas is reported for the first time. Long wavelength (low- k) electron temperature (T e / T e) and high- k density turbulence levels (n e / n e) are observed to strongly increase during ECH. In contrast, low- k and intermediate- k n e / n e showed little change, whereas the cross-phase between local low- k electron temperature and density fluctuations ( n e T e) was significantly modified. The increase in the electron thermal diffusivity determined from power balance is consistent with the increased turbulent transport correlated with the measured increases in low- k T e / T e and high- k n e / n e. Linear stability analysis using the trapped gyro-Landau fluid (TGLF) model indicates an enhanced growth rate for electron modes e.g., trapped electron mode (TEM) at low- k consistent with the observed modifications in T e / T e and n e T e. TGLF also predicts an increase in high- k electron mode growth rates for normalized wavenumbers k s 7, where electron temperature gradient (ETG) modes exist, which is consistent with the observed increase in high- k n e / n e turbulence
Original language | English |
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Article number | 082504 |
Journal | Physics of Plasmas |
Volume | 18 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2011 |
Externally published | Yes |
Funding
This work supported by the U.S. Department of Energy under DE-FG02-08ER54984, DE-FC02-04ER54698, DE-FG02-89ER53296, DE-FG02-08ER54999, DE-AC02-09CH11466, and DE-FC02-93ER54186.
Funders | Funder number |
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U.S. Department of Energy | DE-FG02-08ER54999, DE-FG02-08ER54984, DE-AC02-09CH11466, DE-FC02-04ER54698, DE-FC02-93ER54186, DE-FG02-89ER53296 |