fa عمومى General كاربردي Applicable <p class="Abstract" style="text-align: justify;">The distribution function of<span dir="RTL"> </span>the electrons produced in the interaction between an intense<span dir="RTL"> </span>electromagnetic wave and a neutral gas is derived and is shown to<span dir="RTL"> </span>be nonequilibrium and anisotropic. By assuming that the time scale of gas ionization is<span dir="RTL"> </span>much greater than the field period, it is shown that the electron<span dir="RTL"> </span>distribution function formed in microwave and optical<span dir="RTL"> </span>discharges has sharp anisotropy<span dir="RTL"> </span>affecting the discharge plasma. The anisotropy stimulated by the<span dir="RTL"> </span>inequality of average longitudinal and transverse energy of<span dir="RTL"> </span>electrons is investigated. Furthermore, the parametric<span dir="RTL"> </span>instability stimulated by scattering of incident wave on the<span dir="RTL"> </span>density oscillation of plasma under the positive slope of EDF<span dir="RTL"> </span>with respect to velocity is studied.</p> 33 38 http://ijop.ir/browse.php?a_code=A-10-1-44&slc_lang=fa&sid=1 B. Shokri 10031947532846001872 10031947532846001872 Yes Physics Department and Laser-Plasma Institute of Shahid Beheshti University