RUDI GAELZER
Departamento de Física - Instituto de Física - Universidade Federal do Rio Grande do Sul
Av. Bento Gonçalves, 9500 - Caixa Postal 15051 - 91501-970 - Porto Alegre-RS - Sala N206 (Prédio 43134) (rudi.gaelzer@ufrgs.br) (email)
Av. Bento Gonçalves, 9500 - Caixa Postal 15051 - 91501-970 - Porto Alegre-RS - Sala N206 (Prédio 43134) (rudi.gaelzer@ufrgs.br) (email)
Known radiation emission mechanisms in plasmas include bremmstrahlung (or free-free emission), gyro- and synchrotron radiation, cyclotron maser, and plasma emission. For unmagnetized plasmas, only bremmstrahlung and plasma emissions are viable. Of these, bremmstrahlung becomes inoperative in the absence of collisions, and the plasma emission requires the presence of electron beam, followed by various scattering and conversion processes. The present Letter proposes a new type of radiation emission process for plasmas in a state of thermodynamic quasi-equilibrium between particles and enhanced Langmuir turbulence. The radiation emission mechanism proposed in the present Letter is not predicted by the linear theory of thermal plasmas, but it relies on nonlinear wave-particle resonance processes. The electromagnetic particle-in-cell numerical simulation supports the new mechanism.