Estimate of the maximum induced magnetic field in relativistic shocks

Ghorbanalilu, M.; Sadegzadeh, S.

doi:10.1093/mnras/stw2478

Cited by 9 publications

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Extension of temperature anisotropy Weibel instability to non-Maxwellian plasmas by 2D PIC simulation

Ghorbanalilu

Abdollahazadeh

2017

Laser Part. Beams

View full text Add to dashboard Cite

The Weibel instability driven by temperature anisotropy is investigated in a two-dimensional (2D) particle-in-cell simulation in non-extensive statistics in the relativistic regime. In order to begin the simulation, we introduced a new 2D anisotropic distribution function in the context of non-extensive statistics. The heavy ions considered to be immobile and form the neutralizing background. The numerical results show that non-extensive parameterqplays an important role on the magnetic field saturation time, the time of reduction temperature anisotropy, evolution time to the quasi-stationary state, and the peak energy density of magnetic field. We observe that the instability saturation time increases by increasing the non-extensive parameterq. It is shown that structures with superthermal electrons (q< 1) could generate strong magnetic fields during plasma thermalization. The simulation results agree with the previous simulations for an anisotropic Maxwellian plasma (q= 1).

show abstract

Extension of temperature anisotropy Weibel instability to non-Maxwellian plasmas by 2D PIC simulation

Ghorbanalilu

Abdollahazadeh

2017

Laser Part. Beams

View full text Add to dashboard Cite

show abstract

A comparative study of the filamentation and two-stream instabilities in weakly relativistic counter-streaming plasmas

Ghorbanalilu

Sadegzadeh

2017

Physics of Plasmas

View full text Add to dashboard Cite

Counter-streaming plasma structures are ubiquitous in astrophysical sources of non-thermal radiations. We discuss the dispersion properties and the stability of this non-thermal particle distribution, which is modeled on the basis of the relativistic Jüttner-Maxwell distribution function in the correct laboratory frame of reference. In this work, we aim to construct analytical solutions of the dispersion relations and investigate the properties of the growth rate of the filamentation and two-stream instabilities in an unmagnetized and homogeneous counter-propagating plasma. The Maxwell and the relativistic Vlasov equations are used to derive the covariant dispersion relations that are valid in any (conveniently chosen) reference frame. Aperiodic solutions (ℜ(ω)≃0) to the covariant dispersion relations of the growing modes (ℑ(ω)>0) are demonstrated with the aid of analytical calculations. The dependence of the growth rate on the normalized bulk velocity β0=V0/c and thermal parameter μ=mc2/KBT is shown in graphic illustrations. We found that for both kinds of instabilities, growth rates are decreased by increasing the temperature and decreasing the bulk velocity. Therefore, the electrons at sufficiently low temperatures and with relativistic streams are capable of increasing the range of unstable wave numbers and consequently prevent the instability to cease at small wave numbers. The results indicate that under the same condition and in contrast to the non-relativistic regime, the filamentation instability has the largest growth rate and the electrostatic two-stream instability is in the next place.

show abstract

Maxwell-Jüttner distributed counterstreaming magnetoplasmas—Parallel propagation

Sadegzadeh

Mousavi

2018

Physics of Plasmas

View full text Add to dashboard Cite

Counterstreaming beams of charged particles are frequently observed in the laboratory and space plasma systems, and they are responsible for supplying the free energy of the system in the absence of temperature anisotropies. Such systems are unstable and give rise to excitation of various electrostatic and electromagnetic plasma waves. This work is intended as a supplement to the previous investigations of the Maxwell-Jüttner distributed counterstreaming plasmas on the basis of the covariant (fully relativistic) formulation. Here, we aim to find analytical solutions of the dispersion relations and investigate the properties of the growth rate for the electrostatic and electromagnetic modes propagating parallel to the background magnetic field. The influences of the important parameters of the beam, namely, velocity, temperature, the relative intensity of the two streams, and the strength of the stationary magnetic field, on the growth rates of the longitudinal and transverse modes are compared. The analytical evaluation of the parallel modes reveals several interesting results. First, for all investigated modes, the growth rate is minimum only if the particle distribution function is exactly symmetric. Second, the behavior of the electrostatic and electromagnetic instabilities by varying the beam temperature is totally opposite. Third, increasing the drift velocity, the growth rate exhibits a maximum at a certain velocity; however, beyond that, wave damping occurs. Finally, under the same conditions, the external magnetic field has a destabilizing (stabilizing) effect on the left (right)-hand branch of the transverse modes.

show abstract

Estimate of the maximum induced magnetic field in relativistic shocks

Cited by 9 publications

References 49 publications

Extension of temperature anisotropy Weibel instability to non-Maxwellian plasmas by 2D PIC simulation

Extension of temperature anisotropy Weibel instability to non-Maxwellian plasmas by 2D PIC simulation

A comparative study of the filamentation and two-stream instabilities in weakly relativistic counter-streaming plasmas

Maxwell-Jüttner distributed counterstreaming magnetoplasmas—Parallel propagation

Contact Info

Product

Resources

About