The detailed analysis of plasma maser interaction between high-frequency el
ectromagnetic waves with right-handed polarization (R mode) and electrostat
ic Langmuir waves excited by an electron beam is presented. The analysis sh
ows that generation of R-mode radiation near 2 omega(pe) is possible only f
or magnetized plasmas; here omega(pe) is the electron plasma frequency. Sim
ulations using a two-dimensional electromagnetic and relativistic particle
code show that high-frequency electromagnetic waves with right-handed polar
ization (R mode) can be generated by a plasma maser mechanism from electros
tatic Langmuir waves excited by an electron beam. (C) 1999 American Institu
te of Physics. [S1070-664X(99)04003-3].