Evaluation of Synchrotron Radiation in a Reactor-Grade Tokamak Plasma

Recent research on synchrotron radiation from a magnetically confined plasma has pointed out that the synchrotron radiation makes a significant contribution to the local electron power balance of a high temperature fusion plasma such as ITER's. In this study, synchrotron radiation in a reactor-grade tokamak plasma has been evaluated taking account of relativistic treatment, magnetic structure, propagation direction and torus shape. An extended Trubnikov's equation for the spherically symmetric relativistic Maxwellian velocity distribution [1] is used for the emissivity in the oblique propagation. It is found that synchrotron radiation of extraordinary mode increases with the angle ($\phi$) between the propagation direction and the magnetic field monotonically, and that the synchrotron radiation of ordinary mode has peaks around $\phi$=60--75$^{\circ}$, because the emissivity decreases and the temperature in passing plasma region increases with the $\phi$. Calculation also shows that the total synchrotron radiation is proportional to the 0.5th power of electron density.\\[4pt] [1] M. Sato and A. Isayama, Fusion Sci. Technol. 52 (2007) 169.