New longitudinal mode and compression of pair ions in plasma

Abstract

Positive and negative ions forming so-called pair plasma differing in sign of their charge but asymmetric in mass and temperature support a new acoustic-ike mode. The condition for the excitation of ion sound wave through electron beam induced Cherenkov instability is also investigated. This beam can generate a perturbation in the pair ion plasmas in the presence of electrons when there is number density, temperature and mass difference in the two species of ions. Basic emphasis is on the focusing of ion sound waves and we show how, in the area of localization of wave energy, the density of pair particles increases while electrons are pushed away from that region.Further, this localization of wave is dependent on the shape of the pulse. Considering the example of pancake and bullet shaped pulses, we find that only the former leads to compression of pair ions in the supersonic regime of the focusing region. Here possible existence of regions where pure pair particles can exist may also be speculated which is not only useful from academic point of view but also to mimic the situation of plasma (electron positron asymmetric and symmetric ) observed in astrophysical environment.

Twisted waves in symmetric and asymmetric bi-ion kappa-distributed plasmas

“…(Ali et al [2016]) 10 considered the Landau damping of twisted dusty plasma modes in the Maxwellian environment. A few years ago, the possibility of a longitudinal acoustic mode was predicted for asymmetric pair-ion plasma 11 . A comparable effort was made to investigate acoustic modes in dust-bi-ion electron (DBIE) plasma with heavier negative ions 12 .…”

Effect of arbitrary temperature degeneracy and ion magnetization on shear Alfven waves in electron‐positron‐ion plasmas

“…where the components of is for e-p-i plasma are found by applying Equations (23) and (24) in Equation (22) as.…”

“…[ 22,23 ] This breaks the symmetry of equal mass and number of pair particles, which leads to interesting and new research for the scientists. [ 24,25 ]…”

“…[22,23] This breaks the symmetry of equal mass and number of pair particles, which leads to interesting and new research for the scientists. [24,25] Shear (or torsional) Alfven wave (SAW) is a magnetic hydrodynamic wave which propagation is angle dependent and its propagation vector makes a small angle with magnetic field (B 0 ). While in the case of pure Alfven wave propagation, the vector is parallel to B 0 .…”

Modulation instability of lower hybrid waves leading to cusp solitons in electron–positron(hole)–ion Thomas Fermi plasma

“…Here, unlike usual pair plasmas with the same mass and charge, electrons and holes (positrons) have mass asymmetry, which is either due to interaction between the particles or some other non‐linear phenomena emerging naturally or due to the different mobility of charge carriers. This mass asymmetry, however, opens up an interesting avenue for the plasma physicists to study the waves and instabilities on different time scales, such as low and high frequencies in comparison to gyro frequencies of the particles …”