The Polarization of Bremsstrahlung X-Rays Emitted from an ECR Plasma

The degree of polarization of Bremsstrahlung X-rays emitted from an ECR plasma of high electron temperature has been studied. It has been found that the X-rays emitted from the resonance zone of the plasma have a high degree of polarization and it nears unity for high energy photons. Numerical calculations on the degree of polarization have been performed with the non-relativistic and relativistic cross-sections for Bremsstrahlung. The former is in good agreement only with the X-rays from the off-resonance zone, but the latter is in good agreement with those from the resonance zone. From these calculations, it has also been found that the electron velocity distribution of the plasma produced in this study is extremely anisotropic at the resonance zone, that is, the electron temperatures perpendicular and parallel to the mirror axis are estimated to be about 500 keV and 50 keV, respectively.