Fast reconnection of magnetic fields in turbulent fluids
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| Format: | Artículo científico |
| Sprache: | en |
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Universidad Nacional Autónoma de México
2000
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| _version_ | 1876441994429988864 |
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| author | A. Lazarian |
| author_facet | A. Lazarian |
| contents | Fast reconnection of magnetic fields in turbulent fluids A. Lazarian E. Vishniac Física, Astronomía y Matemáticas MHD SUN: MAG NETIC FIELDS MAGNETIC FIELDS ISM: MAGNETIC FIELDS Reconnection is the process by which magnetic elds in a conducting uidchange their topology. This process is essential for understanding a wide variety ofastrophysical processes, including stellar and galactic dynamos and astrophysicalturbulence. To account for solar ares, solar cycles, and the structure of the galacticmagnetic eld, reconnection must be fast, propagating with a speed close to theAlfven speed. Earlier attempts to deal with magnetic reconnection assumed thatmagnetized uids are laminar and as a result obtained slow reconnection rates.We show that the presence of a random magnetic eld component substantiallyenhances the reconnection rate and enables fast reconnection, i.e., reconnectionthat does not depend on uid resistivity. The enhancement of the reconnectionrate is achieved via a combination of two e ects. First of all, only small segments ofmagnetic eld lines are subject to direct Ohmic annihilation. Thus the fraction ofmagnetic energy that goes directly into uid heating goes to zero as uid resistivityvanishes. However, the most important enhancement comes from the fact thatunlike the laminar uid case where reconnection is constrained to proceed line byline, the presence of turbulence enables many magnetic eld lines to enter thereconnection zone simultaneously. A signicant fraction of magnetic energy goesinto MHD turbulence and this enhances reconnection rates through an increase inthe eld stochasticity. In this way magnetic reconnection becomes fast when eldstochasticity is accounted for. As a consequence solar and galactic dynamos arealso fast, i.e., do not depend on uid resistivity. 2000 artículo científico 0185-1101 https://www.redalyc.org/articulo.oa?id=57100912 en http://www.redalyc.org/revista.oa?id=571 Revista Mexicana de Astronomía y Astrofísica application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Astronomía y Astrofísica (México) Vol.9 |
| format | Artículo científico |
| id | redalyc_57100912 |
| institution | Redalyc |
| language | en |
| publishDate | 2000 |
| publisher | Universidad Nacional Autónoma de México |
| spellingShingle | Fast reconnection of magnetic fields in turbulent fluids A. Lazarian Física, Astronomía y Matemáticas MHD SUN: MAG NETIC FIELDS MAGNETIC FIELDS ISM: MAGNETIC FIELDS Fast reconnection of magnetic fields in turbulent fluids A. Lazarian E. Vishniac Física, Astronomía y Matemáticas MHD SUN: MAG NETIC FIELDS MAGNETIC FIELDS ISM: MAGNETIC FIELDS Reconnection is the process by which magnetic elds in a conducting uidchange their topology. This process is essential for understanding a wide variety ofastrophysical processes, including stellar and galactic dynamos and astrophysicalturbulence. To account for solar ares, solar cycles, and the structure of the galacticmagnetic eld, reconnection must be fast, propagating with a speed close to theAlfven speed. Earlier attempts to deal with magnetic reconnection assumed thatmagnetized uids are laminar and as a result obtained slow reconnection rates.We show that the presence of a random magnetic eld component substantiallyenhances the reconnection rate and enables fast reconnection, i.e., reconnectionthat does not depend on uid resistivity. The enhancement of the reconnectionrate is achieved via a combination of two e ects. First of all, only small segments ofmagnetic eld lines are subject to direct Ohmic annihilation. Thus the fraction ofmagnetic energy that goes directly into uid heating goes to zero as uid resistivityvanishes. However, the most important enhancement comes from the fact thatunlike the laminar uid case where reconnection is constrained to proceed line byline, the presence of turbulence enables many magnetic eld lines to enter thereconnection zone simultaneously. A signicant fraction of magnetic energy goesinto MHD turbulence and this enhances reconnection rates through an increase inthe eld stochasticity. In this way magnetic reconnection becomes fast when eldstochasticity is accounted for. As a consequence solar and galactic dynamos arealso fast, i.e., do not depend on uid resistivity. 2000 artículo científico 0185-1101 https://www.redalyc.org/articulo.oa?id=57100912 en http://www.redalyc.org/revista.oa?id=571 Revista Mexicana de Astronomía y Astrofísica application/pdf Universidad Nacional Autónoma de México Revista Mexicana de Astronomía y Astrofísica (México) Vol.9 |
| title | Fast reconnection of magnetic fields in turbulent fluids |
| topic | Física, Astronomía y Matemáticas MHD SUN: MAG NETIC FIELDS MAGNETIC FIELDS ISM: MAGNETIC FIELDS |
| url | https://www.redalyc.org/articulo.oa?id=57100912 |