Helicity transformation under the collision and merging of two magnetic flux ropes
- Univ. of California, Los Angeles, CA (United States)
Magnetic helicity has become a useful tool in the analysis of astrophysical plasmas. Its conservation in the magnetohydrodynamic limit (and other fluid approaches) constrains the global behavior of large plasma structures. One such astrophysical structure is a magnetic flux rope: a tube-like, current-carrying plasma embedded in an external magnetic field. Bundles of these ropes are commonly observed in the near-earth environment and solar atmosphere. In this well-diagnosed experiment (three-dimensional measurements of ne, Te, Vp, B, J, E, and uflow), two magnetic flux ropes are generated in the Large Plasma Device at UCLA. These ropes are driven kink-unstable to trigger complex motion. As they interact, helicity conservation is examined in regions of reconnection. We examine (1) the transport of helicity and (2) the dissipation of the helicity. As the ropes move and the topology of the field lines diverge, a quasi-separatrix layer (QSL) is formed. As the QSL forms, magnetic helicity is dissipated within this region. Here, at the same time, there is an influx of canonical helicity into the region such that the temporal derivative of magnetic helicity is zero
- Research Organization:
- Univ. of California, Los Angeles, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- FC02-07ER54918
- OSTI ID:
- 1474289
- Alternate ID(s):
- OSTI ID: 1367936
- Journal Information:
- Physics of Plasmas, Vol. 24, Issue 7; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Quantifying reconnective activity in braided vector fields
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journal | July 2018 |
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