view Abstract Citations (11) References (17) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Plasma Radiation from Collisionless MHD Shock Waves. II. Plasmawave Generation and Transformation Processes Smith, D. F. Abstract The distribution of plasma waves which results when beams of electrons produced in a collisonless magnetohydrodynamic shock wave enter into the upstream plasma is examined. The upstream region is divided into two parts, a relaxation region in which the beams lose their directed energy and a forward region to which plasma waves with sufficiently high group velocity escape. Losses of plasma waves in the relaxation region due to escape to the forward region and into the shock are taken into account to establish a minimum beam density for self-consistency. Nonlinear processes are analyzed to determine the angular distribution of plasma waves. Processes for the transformation of plasma waves into radiation are considered. It is shown that interaction of plasma waves with the density inhomogeneity of the shock front will lead to negligible radiation. The process p + s t, where p is a plasma wave, S is an ion-acoustic wave, and t is a transverse wave, will not be important in the shock front due to the difficulty in satisfying the momentum conservation condition. The only significant transformation process for emission near the fundamental of the plasma frequency in the shock front and the upstream region is scattering on the polarization clouds of ions, p + i H t(wp) + i', where i is an ion. The absorption coefficient for this process can be negative, and hence a transfer problem must be solved to determine the total radiation. The only important transformation process for emission near the second harmonic of the plasma frequency is combination of two excited plasma waves, p + p H t( ). Since the cone of plasma waves is anisotropic and the two excited plasma waves must meet almost "head-on," spontaneous scattering of plasma waves must be taken into account in computing this combination process. Because the shock front is much narrower than the relaxation or forward regions, only the latter need to be considered in computing the radiation. Publication: The Astrophysical Journal Pub Date: May 1972 DOI: 10.1086/151474 Bibcode: 1972ApJ...174..121S full text sources ADS | Related Materials (2) Part 1: 1971ApJ...170..559S Part 3: 1972ApJ...174..643S