Turbulent plasma transport and heating in thin boundary layers

Plasmas are ubiquitous in solar and astrophysical environments and are often essentially collisionless, meaning particle-particle collisions cannot account for heating or transport in these plasmas.

Instead, such processes result from the interaction of particles with electromagnetic fields, typically in the form of wave-particle interactions.

Quantifying the effect of wave-particle interactions on transport and heating observationally has proved challenging because particle detectors onboard spacecraft and in laboratory experiments have generally lacked the necessary temporal resolution. Enormous plasma volumes are separated by relatively thin boundaries, where particles are heated.

Similarly, particles can also be transported across the boundaries, which modifies the properties of the boundary.

The plasma inhomogeneities associated with boundaries are an important source of waves, which can grow to large amplitudes and reach a turbulent stage, leading to the particle heating and transport.

Here we use the novel high-resolution data from the four Magnetospheric Multiscale (MMS) mission spacecraft to provide quantitative measures of plasma transport and heating at boundary layers in collisionless plasmas.

These spacecraft have the unique capability to directly measure both electromagnetic fields and the changes in the associated particle velocity distribution functions at high enough frequency to resolve the turbulence.

The goals of this project are: (1) To develop a statistical framework to quantify the transport and heating generated by turbulence at plasma boundaries from direct measurements. (2) To statistically quantify the role of turbulence in particle transport and heating at plasma boundaries, specifically at Earth’s magnetopause and magnetotail.