Suppression of runaway electrons during electron cyclotron resonance heating on HL-2A tokamak

Abstract

The statistical analysis of heating effect and the cross-correlation analysis of both electron temperature and loop voltage have been done during electron cyclotron resonance heating (ECRH). The behavior of runaway electrons in the flattop phase during ECRH are analyzed using experimental data. It is shown that the runaway population is indeed suppressed or even quenched when the toroidal electric field E T is reduced below the threshold electric field E th by high-power and long-duration ECRH. The physical mechanism of runaway suppression is explored by the resonant interaction between the electron cyclotron waves and the energetic runaway electrons.

Development of hard X-ray spectrometer with full digital data acquisition for runaway electron studies at HL-2M

“…Large-sized NaI:Tl crystal coupled to a photomultiplier tube is used in our HXR system. Figure 1 displays the inside structure of this detector, it has been widely used in many fusion devices, such as FTU [18], Damavand tokamak [19] and HL-2A [12,13,15].…”

“…Both MGI and SPI are favorable to controlling RE beam position in Tokamak à Configuration Variable (TCV) [11]. In Huan-Liuqi-2A (HL-2A) experiments, the observed picture of long-lived RE beams provides a possibility of suppressing or mitigating the REs by MGI [12] and Electron Cyclotron Wave (ECW) [13,14]. During the simultaneous application of Lower Hybrid Wave (LHW) and ECW, REs cannot be created when LH power is switched off, but it's observed to be enhanced when EC power is switched off [15].…”

Investigation of relativistic runaway electrons in electron cyclotron resonance heating discharges on Korea Superconducting Tokamak Advanced Research

“…It is a well-known phenomenon reported in many papers. 6,10,11 However, an abnormal phenomenon has been observed in the KSTAR tokamak. Figure 3 shows the plasma parameters for the KSTAR discharges # 5964 and 5965.…”

A pulse step modulator cathode power supply for ECRH system on HL-2A Tokamak

“…It is beneficial in controlling the magneto-hydro-dynamic (MHD) instability and in forming reversed shear configuration [1]. The maximum ECRH power on HL-2A is 5MW and is generated by eight gyrotrons.…”