Speaker
Description
Cosmic ray (CR) feedback plays a vital role in shaping the formation and evolution of galaxies through their interaction with magnetohydrodynamic waves. In the CR self-confinement scenario, the waves are generated by the CR gyro-resonant instabilities via CR streaming or CR pressure anisotropy and saturate by balancing wave damping. The resulting effective particle scattering rate by the waves, $\nu_{\text{eff}}$, critically sets the coupling between the CRs and background gas, but the efficiency of CR feedback is yet poorly constrained. We employ 1D kinetic simulations under the Magnetohydrodynamic-Particle-In-Cell (MHD-PIC) framework with the adaptive $\delta f$ method to quantify $\nu_{\text{eff}}$ for the saturated state of the CR pressure anisotropy instability (CRPAI) with ion-neutral friction. We drive CR pressure anisotropy by expanding/compressing box, mimicking the background evolution of magnetic field strength, and the CR pressure anisotropy eventually reaches a quasi-steady state by balancing quasi-linear diffusion. At the saturated state, we measure $\nu_{\text{eff}}$ and the CR pressure anisotropy level, establishing a calibrated scaling relation with environmental parameters. The scaling relation is consistent with quasi-linear theory and can be incorporated to CR fluid models, in either the single-fluid or $p$-by-$p$ treatments. Our results serve as a basis for accurately calibrating the subgrid physics in macroscopic studies of CR feedback and transport.
| Primary Theme | Small to large scales |
|---|---|
| Secondary Theme | Diffuse to dense structures |
| Presenter's Name | XIAOCHEN SUN |
| Presenter's Email Address | [email protected] |
| Keywords | Plasma astrophysics, Alfven waves, Magnetohydrodynamics, Cosmic rays |
| Recording Permission | YES |
| Virtual Audience Permission | YES |
| Photography Permission | YES |
| If your talk is not accepted for a contributed talk, would you be interested in presenting a fireslide/lightning talk? | Yes |
| If your fireslide/lighting talk is not accepted, would you be interested in presenting a poster? | No |
Authors
External references
- 25070049
- e057a6b7-e148-4be0-ba86-908ac5e1b01d
