Particle acceleration and fast magnetic reconnection
Mathematics demonstrates that the exponential separation of neighboring magnetic field lines, which naturally increases during an ideal evolution in three dimensions, leads to an exponentially increasing connection-breaking nonideal magnetic field. On a time scale that depends only logarithmically on the magnitude of the nonideal terms, a fast magnetic reconnection will generally occur, which has a rate determined by Alfvénic, not resistive, physics. The traditional assumption that the reconnecting flux must be dissipated by an electric field is false. In three dimensions, an ideal evolution can spatially mix the magnetic flux. Flux mixing conserves magnetic helicity, which limits the energy that can be transferred from the magnetic field to the plasma. The magnetic evolution is quasi-ideal during a fast magnetic reconnection, and the energy loss is given by the dot product of the magnetic field line velocity $$\vec{μ}_{⊥}$$ with the $$\vec{j}$$ × $$\vec{B}$$ Lorentz force. Energy loss occurs through Alfvén waves and two other effects, which are also present in an ideal evolution. One is an effective parallel electric field ℰ||, which can accelerate particles despite the particle acceleration due to the true parallel electric field E|| being negligible, and a coefficient νK, which gives a rate for exponentiation of the kinetic energy of particle motion along the magnetic field.
- Research Organization:
- Columbia Univ., New York, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- FG02-03ER54696; FG02-95ER54333; SC0018424; SC0019479
- OSTI ID:
- 1609489
- Journal Information:
- Physics of Plasmas, Vol. 26, Issue 8; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Magnetic reconnection with null and X-points
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journal | December 2019 |
| Magnetic reconnection with null and X-points | text | January 2019 |
Flattening of the tokamak current profile by a fast magnetic reconnection with implications for the solar corona
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journal | October 2020 |
| Changed paradigm of fast magnetic reconnection | preprint | January 2020 |
| Magnetic reconnection and thermal equilibration | text | January 2020 |
| Example of exponentially enhanced magnetic reconnection driven by a spatially-bounded and laminar ideal flow | text | January 2020 |
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