Collaborative Research: Three-Dimensional Stability of Kinetic Flux Rope Structures in a Collisionless Magnetized Plasma

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This project will theoretically and computationally study formation of self-organized structures in a plasma. Most observable matter in the universe is in the form of a plasma, consisting of electrically charged particles with electrons freed from atoms. In a plasma, the electrons and the charged atoms (the ions) move quasi-randomly, but their spatial distribution and movement can produce electric and magnetic fields leading to formation of plasma structures with sizes much larger than atomic sizes but much smaller than the volume of the whole plasma. Such small structures can fundamentally change the properties of plasmas. However, whether and how such structures can form is still poorly understood and will be pursued within this project. Results from this research will increase our understandings of properties of space, astrophysical, and laboratory plasmas, with societally important applications for space weather prediction and future fusion energy devices. This collaborative project will support a PhD student at University of Alaska Fairbanks, as well as a PhD student at University of New Hampshire. The students will receive training in both theory and numerical simulations.High temperature plasmas can be considered collisionless, with particle distributions in a collisionless plasma often deviating from a Maxwellian. While the forms of such non-Maxwellian distributions are important, it is also important to explore how small-scale kinetic structures can exist in such plasmas, with the Bernstein-Greene-Kruskal (BGK) modes in 1D being one example. This project will perform numerical simulations using the state-of-the-art Particle-In-Cell (PIC) code "PSC" to study the stability of analytic multi-dimensional solutions of localized kinetic structures in the form of magnetic flux ropes satisfying the Vlasov-Poisson-Ampère system of equations. Possible formation mechanisms for the generation of stable two-dimensional or three-dimensional localized kinetic structures will also be studied numerically. The main goal of this research is to characterize quantitatively the conditions under which kinetic structures can be stable. This project is expected to produce new understanding of small-scale kinetic physics in collisionless magnetized plasmas. New insights obtained through this project will have impact on fundamental plasma theory, as well as affect frontier problems in laboratory, space and astrophysical plasmas. For example, it can have significant implication for understanding the process of magnetic reconnection, where recent large-scale kinetic simulations have discovered the generation of small kinetic scale flux ropes during magnetic reconnection. Small-scale kinetic structures have also been observed by the Magnetospheric Multiscale (MMS) mission, which has the main objective of studying magnetic reconnection in space. Moreover, this project can impact other fields in science since the Vlasov equation is widely applied in many different physical systems. This project is jointly funded by the Division of Physics and the Established Program to Stimulate Competitive Research (EPSCoR).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.