Thermal flux reduction by electromagnetic instabilities

From a dispersion relation, linear growth rates of electromagnetic instabilities are obtained in an electron plasma whose velocity distribution function has a high-energy tail. Theory is developed to derive the reduction in the thermal flux caused by these electromagnetic instabilities. Nonlinear theory leads to the saturation level of instabilities. Numerical simulations are carried out using a particle-in-cell method. The reduction in thermal conduction predicted by the theory is found to be in good agreement with computer simulations.