摘要:Excitation of electrostatic electron cyclotron harmonic (ECH) waves is studied by performing linear dispersion analysis and particle-in-cell computer simulation. The ECH wave emissions can be excited by a positive slope in a velocity distribution function perpendicular to the ambient magnetic field, such as that due to a loss cone or ring velocity distribution. However, there exists no analytic expression for integration of Maxwellian ring velocity distribution functions. Here we present a method to solve the linear dispersion relations of Maxwellian ring velocity distribution functions with numerical integration. The obtained dispersion relations are confirmed by particle-in-cell simulation.