The numerical simulation of the generation of lower-band VLF chorus using a quasi-broadband Vlasov Hybrid Simulation code

In this paper, we perform the numerical modelling of lower-band VLF chorus in the earth’s magnetosphere. Assuming parallel propagation the 1d3v code has one spatial dimension z along the ambient magnetic field, which has a parabolic z dependence about the equator. The method used is Vlasov Hybrid Simulation (VHS) also known in the literature as the method of Kinetic Phase Point Trajectories (Nunn in Computer Physics Comms 60:1–25, 1990, J Computational Phys 108(1):180–196, 1993; Kazeminezhad et al. in Phys Rev E67:026704, 2003). The method is straightforward and easy to program, and robust against distribution function filamentation. Importantly, VHS does not invoke unphysical smoothing of the distribution function. Previous versions of the VLF/VHS code had a narrow bandwidth ~ 100 Hz, which enabled simulation of a wide variety of discrete triggered emissions. The present quasi-broadband VHS code has a bandwidth of ~ 3000 Hz, which is far more realistic for the simulation of chorus in its entirety. Further, the quasi-broadband code does not require artificial saturation, and does not need to employ matched filtering to accommodate large spatial frequency gradients. The aim of this paper which has been achieved is to produce VLF chorus Vlasov simulations employing a systematic variety of triggering input signals, namely key down, single pulse, PLHR, and broadband hiss. Graphical Abstract

The Numerical Simulation of the Generation of Lower Band VLF Chorus Using a Quasi-Broadband Vlasov Hybrid Simulation Code

In this paper we perform the numerical modelling of lower band VLF chorus in the earth’s magnetosphere. Assuming parallel propagation the 1d3v code has one spatial dimension z along the ambient magnetic field, which has a parabolic z dependence about the equator. The method used is Vlasov Hybrid Simulation (VHS) also known in the literature as the method of Kinetic Phase Point Trajectories (Nunn 1990,1993; Kazeminezhad et al. 2003). The method is straightforward and easy to program, and robust against distribution function filamentation. Importantly VHS does not invoke unphysical smoothing of the distribution function. Previous versions of the VLF/VHS code had a narrow bandwidth ~100Hz, which enabled simulation of a wide variety of discrete triggered emissions. The present quasi-broadband VHS code has a bandwidth of ~3000Hz, which is far more realistic for the simulation of chorus in its entirety. Further the quasi-broadband code does not require artificial saturation, and does not need to employ matched filtering to accommodate large spatial frequency gradients. The aim of this paper which has been achieved is to produce VLF chorus Vlasov simulations employing a systematic variety of triggering input signals, namely key down, single pulse, PLHR, and broadband hiss.

Quasi-parallel propagation of solitary waves in magnetised non-relativistic electron–positron plasmas

We study the propagation of nonlinear waves in non-relativistic electron–positron plasmas. The waves are assumed to propagate at small angles with respect to the equilibrium magnetic field. We derive the equation describing the wave propagation under the assumption that the waves are weakly dispersive and also can weakly depend on spatial variables orthogonal to the equilibrium magnetic field. We obtain solutions of the derived equation describing solitons. Then we study the stability of solitons with respect to transverse perturbations.

The magnetic field quantization in pulsar

<p>Magnetic field quantization is an important issue for degenerate environments such as neutron star, radio pulsars and magnetars etc., due to the fact that these stars have magnetic field even more than the quantum critical field strength of the order of 4.4×10¹³G, accordingly the cyclotron energy may be equal or even much more than the Fermi energy of degenerate particles. We shall formulate here the exotic physics of strongly magnetized neutron star. The effect of quantized anisotropic magnetic pressure, arising due to a strong magnetic field is studied on the growth rate of Jeans instability of quantum electron–ion and classical dusty plasma.  Here we shall formulate the dispersion equations to govern the propagation of the gravitational waves both in perpendicular and parallel directions to the magnetic field, respectively.  We will depict here that the quantized magnetic field will result in Jeans anisotropic instability such that for perpendicular propagation, the quantized magnetic pressure will stabilize Jeans instability, whereas for the parallel propagation the plasma become more unstable.  We also intend to calculate the corresponding Jeans wave number in the absence of tunneling. The Madelung term leads to the inhomogeneity of the plasma medium. Numerical results are presented to show the effect of the anisotropic magnetic pressure on the Jeans instability.</p>