The effect of LH (lower hybrid) wave frequency on lower hybrid current drive (LHCD) characteristics has been studied on EAST for the first time with two different frequencies (2.45 and 4.6 GHz), showing that higher frequency improves penetration of the RF power into the plasma core, leading to a better effect on plasma characteristics. The improvement in LHCD is mainly ascribed to a reduction in parametric instability (PI) and a lesser extent collisional absorption (CA) in the edge region with the 4.6 GHz wave, demonstrating the role and mitigation of parasitic effects of edge plasma. These results are encouraging that LHCD is essential for current profile control in reactor grade plasmas. © 2017 IOP Publishing Ltd.
Observation and mitigation of parasitic effects of edge plasma by higher operating frequency in LHCD experiments in EAST
Cardinali, A.;Napoli, F.;Ceccuzzi, S.;Tuccillo, A.A.;Cesario, R.;Castaldo, C.
2017-01-01
Abstract
The effect of LH (lower hybrid) wave frequency on lower hybrid current drive (LHCD) characteristics has been studied on EAST for the first time with two different frequencies (2.45 and 4.6 GHz), showing that higher frequency improves penetration of the RF power into the plasma core, leading to a better effect on plasma characteristics. The improvement in LHCD is mainly ascribed to a reduction in parametric instability (PI) and a lesser extent collisional absorption (CA) in the edge region with the 4.6 GHz wave, demonstrating the role and mitigation of parasitic effects of edge plasma. These results are encouraging that LHCD is essential for current profile control in reactor grade plasmas. © 2017 IOP Publishing Ltd.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
