Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The Poison‐Vlasov model in plasma kinetic theory is taken into account to study the propagation of electron plasma waves (or Langmuir waves) in hot, un‐magnetized Vasyliunas‐Cairns distributed plasmas (VCDPs). The longitudinal dielectric plasma response function is obtained for such nonthermal plasmas. The Landau damping rate of Langmuir waves (LWs) in nonthermal VCDP, which propagates with a phase speed greater than the effective thermal speed of the electrons, is also studied. The real and imaginary parts of the wave frequency are investigated analytically as well as numerically and a comparison between the numerical and analytical results is presented. The finding reveals that the dispersion curve and damping rate of the wave are significantly influenced by the simultaneous presence of two nonthermality parameters, that is, ′<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra56661-math-0001.png" xlink:title="urn:x-wiley:21699380:media:jgra56661:jgra56661-math-0001" />′ and ′<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra56661-math-0002.png" xlink:title="urn:x-wiley:21699380:media:jgra56661:jgra56661-math-0002" />′ (spectral index) in the hybrid (Vasyliunas‐Cairns) distributed plasmas. It is discussed that results are quite distinctive from that obtained in nonthermal plasmas that have sole presence of either of the nonthermality parameters ′<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra56661-math-0003.png" xlink:title="urn:x-wiley:21699380:media:jgra56661:jgra56661-math-0003" />′ or super‐thermality spectral index ′<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/jgra56661-math-0004.png" xlink:title="urn:x-wiley:21699380:media:jgra56661:jgra56661-math-0004" />′ in Cairns or kappa distributed electron plasmas, respectively. The more realistic form of 3D and reduced 1D distribution function of VCDP has been used to analyze LWs in describing nonthermal plasmas with more energetic electron in VCDP case.</jats:p>