# Plasma Physics

When waves reach large amplitudes in plasma, they modify the plasma properties. This can lead to their self-focusing into intense soliton-like structures that can collapse to short scales, generating secondary waves and accelerating fast particles. When pumped by an energy source such as a radar or laser, a turbulent state of such solitons can develop, generating a spectrum of electromagnetic wave emission. We have developed the first computer code able to study large-scale nonlinear electromagnetic plasma turbulence, and aim to apply it to obtain the first predictions of many phenomena in this area.

In turbulent plasmas, waves often scatter strongly as they propagate, with the result that they random-walk out of their source region. This leads to random wave growth, extended emission, frequency shifts, and depolarization of the radiation, with important observational consequences in applications to laboratory and space plasmas. We are currently generalizing the theory of such stochastic wave growth to encompass all these effects simultaneously.

Numerous areas exist for PhD, MSc, or Honors projects, which could include theoretical, computational, and experimental components in cooperation with our international and local collaborators. In particular, we have access to laboratory and spacecraft wave data against which to test theoretical and computational predictions. Spacecraft data includes wave measurements from STEREO on which Prof. Robinson and Prof. Cairns are Investigators.

Specific projects lie in areas including:

- Using large-scale computations, based on the Zakharov and nonlinear Schroedinger equations, to determine the statistical properties of nonlinear electromagnetic plasma turbulence, especially those involving the electromagnetic waves themselves, and their interactions with plasma inhomogeneities.
- Developing statistical soliton-gas theories of electromagnetic plasma turbulence.
- Developing a combined theory of scattering, stochastic growth, and depolarization, and applying it to understand the properties of solar radio bursts and other emissions.
- Predicting observational consequences of nonlinear plasma turbulence and other nonlinear and stochastic plasma phenomena, and testing these against laboratory and space data.