5:15 PM - 6:45 PM
[PEM17-P14] Precursor wave emissions from relativistic shocks in electron-positron-ion plasma
Keywords:relativistic shock, fast radio burst, PIC simulation
In 2007, a very bright radio wave emitted for a few milliseconds was found and named "fast radio burst (FRB)." FRBs have very high brightness temperatures and strong linear polarization. To explain these observational features, the magnetar flare model has been proposed, in which energy releases from the magnetars make relativistic shock and emit FRBs. It has been studied that electromagnetic waves were emitted from relativistic shocks in two-component plasma, such as pair plasma and ion-electron plasma, using particle-in-cell (PIC) simulations (e.g., Iwamoto et al., 2017; 2019). However, three-component plasma (electron, positron, and ion) has not been extensively studied (Hoshino and Arons, 1991; Amato and Arons, 2006). In this study, we examined properties of the precursor waves from relativistic shocks by using the 1-D PIC simulation code, pCANS.
We have investigated structures and energies of emitted precursor waves by changing the ratio of positrons to electrons and the ratio of the Poynting flux to the plasma kinetic energy (sigma parameter). As a result, we found that the structures of precursor waves can be categorized into three types depending on the ratio of positrons to electrons and the sigma parameter. Furthermore, we found that emissions of the precursor waves become inefficient when the sigma parameters are relatively high and the ratio of positrons to electrons is close to 0.6. We also found wave packets in specific parameter space, which can correspond to the transient property of FRBs. In this presentation, we report whether the precursor wave emissions in three-component plasma are consistent with the observational properties of FRBs based on precursor wave energies and the width of wave packets.
We have investigated structures and energies of emitted precursor waves by changing the ratio of positrons to electrons and the ratio of the Poynting flux to the plasma kinetic energy (sigma parameter). As a result, we found that the structures of precursor waves can be categorized into three types depending on the ratio of positrons to electrons and the sigma parameter. Furthermore, we found that emissions of the precursor waves become inefficient when the sigma parameters are relatively high and the ratio of positrons to electrons is close to 0.6. We also found wave packets in specific parameter space, which can correspond to the transient property of FRBs. In this presentation, we report whether the precursor wave emissions in three-component plasma are consistent with the observational properties of FRBs based on precursor wave energies and the width of wave packets.