Interplay between magnetic reconnection and turbulence
| Author(s) | Adhikari, Subash | |
| Date Accessioned | 2023-03-13T11:11:10Z | |
| Date Available | 2023-03-13T11:11:10Z | |
| Publication Date | 2022 | |
| SWORD Update | 2023-02-14T17:06:23Z | |
| Abstract | Reconnection and turbulence frequently occur in plasmas, including laboratory, astrophysical and space plasmas. Over the past few decades, the interrelationship between turbulence and magnetic reconnection has been the focus of increasing scrutiny with significant research on the statistics of reconnection as an element of turbulence, the generation of turbulence due to instabilities associated with reconnection, and the effect of reconnection on the turbulent cascade. However, none of these studies directly address the universal properties that may relate reconnection and turbulence, i.e., ``What are the turbulent-like features of laminar magnetic reconnection?'' and ``Is magnetic reconnection fundamentally an energy cascade?'' To answer these questions, we analyze 2.5D fully kinetic particle-in-cell (PIC) simulations of reconnection and turbulence. First, we start with a laminar anti-parallel reconnection with no initial turbulent fluctuations. Even with no secondary instabilities, the reconnection process in its quasi-steady phase is found to generate a magnetic energy spectrum with a spectral index of -5/3 at scales larger than the ion-inertial length, in accordance with Kolmogorov turbulence. Further, the scale-to-scale energy transfer process is studied using the von-Karman Howarth equation generalized to Hall Magnetohydrodynamic (MHD) systems. Most notably, the energy transfer in laminar magnetic reconnection is also found to be similar to that of a turbulent system suggesting that reconnection involves an energy cascade. Consistent with this similarity, the reconnection rate is positively correlated to both the magnetic energy spectrum in the ion-scales and the cascade of energy. Next, we investigate how robust the antiparallel reconnection results are by generalizing them to reconnection with smaller magnetic shear (guide field reconnection). The guide field does not fundamentally change the energy transfer properties of reconnection. Finally, we study how the electric field spectrum and its constituent physical terms in Ohm's law are modified by changing the guide field in reconnection. Unlike the magnetic spectrum, the electric field spectrum drastically changes with guide field. At MHD length scales, there is a flat spectrum for the antiparallel case and a gradual steepening to a -5/3 slope with increasing guide field. In summary, the striking similarities found between the reconnection and turbulence simulations imply that both processes are fundamentally energy cascades, and raises the intriguing possibility of a fundamental universality linking the two. | |
| Advisor | Shay, Michael A. | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Physics and Astronomy | |
| DOI | https://doi.org/10.58088/5vhs-t028 | |
| Unique Identifier | 1372491437 | |
| URL | https://udspace.udel.edu/handle/19716/32404 | |
| Language | en | |
| Publisher | University of Delaware | |
| URI | https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/dissertations-theses/interplay-between-magnetic-reconnection/docview/2778310747/se-2?accountid=10457 | |
| Keywords | Cascade | |
| Keywords | Magnetic reconnection | |
| Keywords | Turbulence | |
| Keywords | Energy cascade | |
| Keywords | Magnetohydrodynamic systems | |
| Title | Interplay between magnetic reconnection and turbulence | |
| Type | Thesis |