The dispersion relations of parallel propagating modes（Langmuir mode, right and left handed circular polarized waves） in the weak magnetic field limit ｜ω-k·v｜ 〉〉 ？ are considered for ultra-relativistic ar...The dispersion relations of parallel propagating modes（Langmuir mode, right and left handed circular polarized waves） in the weak magnetic field limit ｜ω-k·v｜ 〉〉 ？ are considered for ultra-relativistic arbitrary degenerate electron plasma. The results are presented in terms of moments of Fermi-Dirac distribution. The increase in the electron equilibrium number density from negative large（weakly degenerate） to positive large（highly degenerate） values of μ/Te is observed（where μ is the electron chemical potential and Te is the electron thermal energy）. As a result, shifting of the cutoff points in all the real dispersion branches towards the higher values and increasing in the band gap between unmagnetized longitudinal and transverse modes in k-space are examined. Also, the suppression of the weak magnetic field effects in weakly magnetized right handed and left handed circular polarized waves and a decrease in the longitudinal and transverse screening effects are observed in the graphical patterns due to an increase in the equilibrium number density.展开更多
The separate spin evolution quantum hydrodynamics(SSE-QHD)model is used to investigate the energy behavior for ion acoustic waves in degenerate quantum plasma.Numerical results show that the energy flow speed decrease...The separate spin evolution quantum hydrodynamics(SSE-QHD)model is used to investigate the energy behavior for ion acoustic waves in degenerate quantum plasma.Numerical results show that the energy flow speed decreases with spin polarization parameter.It is also shown that it decreases with the increasing rate up to a certain range of wave number and then it goes to zero asymtotically.It is observed that Bohm potential suppresses the energy flow speed.It is also noticed that the energy flow speed deviates from the group velocity even in the absence of Bohm potential effect.However,the contribution of of Bohm poential effect in spin polarized plasma reduces the extent of deviation.展开更多
The dispersion relations and Landau damping of Alfven waves in kinetic and inertial limits are studied in temperature anisotropic Cairns distributed plasma.In the case of kinetic Alfven waves(KAWs),it is found that th...The dispersion relations and Landau damping of Alfven waves in kinetic and inertial limits are studied in temperature anisotropic Cairns distributed plasma.In the case of kinetic Alfven waves(KAWs),it is found that the real frequency is enhanced when either the electron perpendicular temperature or the non-thermal parameter A increases.For inertial Alfven waves(IAWs),the real frequency is slightly affected by the electron temperature anisotropy and A.Besides the real frequency,the damping rate of KAWs is reduced when the electron perpendicular temperature or A increases.In the case of IAWs,the temperature anisotropy and A either enhance or reduce the damping rate depending upon the perpendicular wavelength.These results may be helpful to understand the dynamics of KAWs and IAWs in space plasmas where the non-Maxwellian distribution of particles are routinely observed.展开更多
基金the grant No. 101/ORIC/17 from the Government College University, Lahore, Pakistan
文摘The dispersion relations of parallel propagating modes（Langmuir mode, right and left handed circular polarized waves） in the weak magnetic field limit ｜ω-k·v｜ 〉〉 ？ are considered for ultra-relativistic arbitrary degenerate electron plasma. The results are presented in terms of moments of Fermi-Dirac distribution. The increase in the electron equilibrium number density from negative large（weakly degenerate） to positive large（highly degenerate） values of μ/Te is observed（where μ is the electron chemical potential and Te is the electron thermal energy）. As a result, shifting of the cutoff points in all the real dispersion branches towards the higher values and increasing in the band gap between unmagnetized longitudinal and transverse modes in k-space are examined. Also, the suppression of the weak magnetic field effects in weakly magnetized right handed and left handed circular polarized waves and a decrease in the longitudinal and transverse screening effects are observed in the graphical patterns due to an increase in the equilibrium number density.
文摘The separate spin evolution quantum hydrodynamics(SSE-QHD)model is used to investigate the energy behavior for ion acoustic waves in degenerate quantum plasma.Numerical results show that the energy flow speed decreases with spin polarization parameter.It is also shown that it decreases with the increasing rate up to a certain range of wave number and then it goes to zero asymtotically.It is observed that Bohm potential suppresses the energy flow speed.It is also noticed that the energy flow speed deviates from the group velocity even in the absence of Bohm potential effect.However,the contribution of of Bohm poential effect in spin polarized plasma reduces the extent of deviation.
文摘The dispersion relations and Landau damping of Alfven waves in kinetic and inertial limits are studied in temperature anisotropic Cairns distributed plasma.In the case of kinetic Alfven waves(KAWs),it is found that the real frequency is enhanced when either the electron perpendicular temperature or the non-thermal parameter A increases.For inertial Alfven waves(IAWs),the real frequency is slightly affected by the electron temperature anisotropy and A.Besides the real frequency,the damping rate of KAWs is reduced when the electron perpendicular temperature or A increases.In the case of IAWs,the temperature anisotropy and A either enhance or reduce the damping rate depending upon the perpendicular wavelength.These results may be helpful to understand the dynamics of KAWs and IAWs in space plasmas where the non-Maxwellian distribution of particles are routinely observed.
