Events on Friday, May 3rd, 2024
- Last Spring Semester class day
- Abstract: *Note: actual end time may vary.* URL:
- A Study of Magnetized Plasma Turbulence in the Nonrelativistic and Relativistic Regimes
- Time: 2:00 pm
- Place: Sterling 1313;
- Speaker: Cristian Vega, Physics Graduate Student
- Abstract: Turbulence is ubiquitous in space and astrophysical plasmas and is believed to play an important role in particle heating and nonthermal acceleration. These plasmas are commonly threaded by an external magnetic field imposed by the object they surround (e.g., planet, star), making magnetized plasma turbulence a problem of significant interest. In this thesis, we use numerical simulations to study two relatively unexplored regimes of magnetized plasma turbulence, viz., the sub-electron inertial scale in nonrelativistic low electron beta plasmas and both the magnetohydrodynamic and kinetic scales in relativistically hot plasmas. Phenomenology is used to model the energy distribution of turbulent fluctuations and particles.
In the nonrelativistic regime studied, energy dissipation is seen to be strongly intermittent, concentrating on electron-scale current sheets. A few of these current sheets exhibit signatures of electron-only reconnection.
The particle energy probability density function in the relativistic regime displays a nonthermal tail of ultrarelativistic particles that goes from power-law-like to log-normal as the guide field is increased. We propose that this can be understood in terms of the acceleration mechanism that dominates in each case. Also noteworthy is the observed intermittency in the spatial distribution of ultrarelativistic particles. - Host: Stas Boldyrev