11:00 〜 11:15
[PEM17-08] Relativistic turbulence driven by relativistic shock-clump interactions
キーワード：MHD乱流、相対論的衝撃波、磁場増幅
Cosmic rays are high-energy charged particles originating from space, with energies ranging from 10^9 eV to 10^20 eV. They are thought to be accelerated by shock waves through scattering in turbulent plasmas. In particular, for the highest-energy cosmic rays, the shock velocity is expected to be very close to the speed of light. To understand particle acceleration by these relativistic shocks, it is crucial to investigate the turbulence properties and magnetic field amplifications around shock waves (Morikawa et al. 2024).
In this study, we focus on turbulence generated by interactions between a relativistic shock and density clumps, which are ubiquitously present in the upstream region. We performed three-dimensional special relativistic magnetohydrodynamic simulations and found that the magnetic field is amplified in the downstream region, consistent with dynamo theory. In addition, we found that the compressive mode is comparable in strength to the solenoidal mode, which is unexpected in non-relativistic cases. Furthermore, additional shock waves propagating into the downstream region are generated through shock-clump interactions. These additional shocks can enhance downstream turbulence and magnetic field amplification via the same mechanism by which the primary shock generates turbulence.
In our talk, we will present the statistical properties of turbulence, including the energy spectra of solenoidal and compressive modes, vorticity generation, and other relevant characteristics. These results provide insights not only into the dynamo mechanism, but also into particle acceleration processes, including stochastic acceleration in turbulence.
In this study, we focus on turbulence generated by interactions between a relativistic shock and density clumps, which are ubiquitously present in the upstream region. We performed three-dimensional special relativistic magnetohydrodynamic simulations and found that the magnetic field is amplified in the downstream region, consistent with dynamo theory. In addition, we found that the compressive mode is comparable in strength to the solenoidal mode, which is unexpected in non-relativistic cases. Furthermore, additional shock waves propagating into the downstream region are generated through shock-clump interactions. These additional shocks can enhance downstream turbulence and magnetic field amplification via the same mechanism by which the primary shock generates turbulence.
In our talk, we will present the statistical properties of turbulence, including the energy spectra of solenoidal and compressive modes, vorticity generation, and other relevant characteristics. These results provide insights not only into the dynamo mechanism, but also into particle acceleration processes, including stochastic acceleration in turbulence.