Author ORCID Identifier

https://orcid.org/0009-0002-9493-6135

Semester

Summer

Date of Graduation

2025

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Physics and Astronomy

Committee Chair

Paul Cassak

Committee Member

Earl Scime

Committee Member

Weichao Tu

Committee Member

Yi-Min Huang

Abstract

Magnetic reconnection is a fundamental plasma process that facilitates the rapid conversion of magnetic energy into particle acceleration, plasma flows, and heating. It plays a central role in explosive astrophysical events such as solar flares, where vast amounts of magnetic energy are released on short time scales. A key structure in many reconnection sites is the magnetic flux rope, a column of plasma carrying current threaded by helical magnetic fields, which is frequently involved in or generated by reconnection. Understanding how reconnection unfolds in such flux rope systems is critical for interpreting both space weather phenomena and laboratory plasma dynamics. This study investigates the three-dimensional dynamics of reconnection in non-parallel flux ropes in the presence of a background magnetic field called a guide field, with particular emphasis on how reconnection spreads. Electron-magnetohydrodynamics (EMHD) simulations using the \texttt{F3D} code are performed under experimentally relevant conditions from the PHAse Space MApping (PHASMA) laboratory device at West Virginia University. These simulations have initial conditions motivated by %reproduce the experimentally observed configuration of two tilted flux ropes initiated by plasma guns in a background magnetic field. The simulations reveal that the reconnection dynamics depends strongly on both the geometry of the flux ropes and the strength of the guide field. In double flux rope configurations, parallel ropes reconnect nearly simultaneously along their length, while non-parallel ropes exhibit zipper-like spreading at low guide fields. As the guide field increases, the spreading direction reverses resulting in reverse zipper reconnection spreading. At intermediate guide field strengths, the flux ropes exhibit a combination of zipper and reverse zipper spreading. These behaviors arise from a competition between rotational and mutual attraction forces on the flux ropes. These findings advance the understanding of three-dimensional reconnection in electron-scale systems and are relevant to space plasmas where guide fields and non-parallel structures are common, such as the solar corona, solar wind, and magnetotail. They also offer insights into interpreting laboratory observations from PHASMA, which serves as the experimental basis for this work.

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