Paul Cassak
Clemson University, SC·Physics
Plasmas are gases so hot that electrons break free from their atoms, leaving a mix of charged particles. A central puzzle in plasma physics is how energy moves between electric and magnetic fields and the plasma's thermal energy, the energy of its particles' random motion.
- Fields
Physics
Astronomy & Astrophysics
Earth & Environmental Science
- Topics
plasma physics
space physics
magnetic reconnection
- Grants
- 1 known grant, through Jun 2027
What they work on
- Measure how energy conversion in non-equilibrium plasmas depends on ambient plasma conditions, using a series of two-dimensional particle-in-cell simulations of magnetic reconnection and turbulence.
- Study secondary islands and flux ropes, twisted magnetic structures that accelerate particles, in two- and three-dimensional reconnection simulations to characterize non-LTE energy conversion at these sites.
- Generalize the non-LTE energy conversion theory to include both random and bulk particle motion, and apply it to simulations of reconnection and turbulence alongside Magnetospheric Multiscale (MMS) satellite data.
More about the research
In space and in fusion devices, plasma particles rarely collide. These weakly collisional plasmas are usually far from local thermodynamic equilibrium (LTE), so a temperature cannot even be defined in the usual way. As a result, standard thermodynamics, including the first law, does not fully describe how their energy changes. This collaborative project builds on a recent result that quantified energy conversion in non-LTE plasmas and aims to carry out the first systematic study of it.
Why it matters
Understanding how weakly collisional plasmas convert energy could improve explanations of solar flares, the geomagnetic substorms that produce aurora and space weather impacts, and the heating of the solar wind. The framework is also expected to be useful in other areas of plasma science, including high energy density and fusion plasmas.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Colby Haggerty
University of Hawaii at Manoa, HI·Physics·Early-career
Determine how a velocity shear between neighboring plasma flows changes the rate, outflow speed and heating of collisionless magnetic reconnection, using kinetic modeling and theory.
Peter Constantin
Princeton University, NJ·Mathematics & Statistics
Develop a new mathematical analysis of radiative kinetics, the equations describing how radiation affects plasma dynamics, as a new direction in applied analysis.
Kun Zhang
Embry-Riddle Aeronautical University-Daytona Beach, FL·Earth & Environmental Science
Measure how the reflection rate, velocity, temperatures and velocity distribution types of freshly reflected ions at Earth's bow shock depend on solar wind speed, interplanetary magnetic field, Mach number, beta and shock angle, using satellite measurements.
The school
Clemson University: 19 labs on PI Pages, $339M a year on research, 297 research doctorates a year.
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