Synchrotron radiation spectra and synchrotron radiation spot shape of runaway electrons in Experimental Advanced Superconducting Tokamak

摘要

A detailed analysis of the spectra of synchrotron radiation emitted by runaway electrons, and an analysis of synchrotron radiation spot shapes are presented for EAST runaway cases. Conditions required for the asymptotic expressions of synchrotron radiation spectra to be valid are studied for these EAST parameters. We provide the correct synchrotron radiation spectra in typical EAST discharges, and we show results of calculations of the shape of the synchrotron radiation spots emitted by runaway electrons. These shapes are detected by a visible light camera in EAST. Safety factor q(r), the horizontal displacement of electron drift surfaces with respect to the magnetic surfaces δ_e, pitch angle θ_p, and the position of the camera were taken into account. Our results indicate that the θ_p and q profiles can significantly affect the synchrotron radiation spot shape; it is simpler to record all synchrotron radiation if the camera is placed far from the plasma. An asymmetrical synchrotron radiation spot shape can be deduced when the effect of the drift orbit shift is taken into account. Our results can explain the asymmetrical ring-like synchrotron radiation spot shape from runaway electron beams in EAST experiments.