Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies
It is well known that interchange instabilities (and associated ballooning modes) in laboratory fusion devices limit the maximum value of the plasma due to per-turbations with a wave vector perpendicular, or nearly perpendicular, to the mag-netic field. For those perturbations, the field line bendin...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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2006
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| _version_ | 1797071767119855616 |
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| author | Goedbloed, J Blokland, J Keppens, R Schure, K |
| author_facet | Goedbloed, J Blokland, J Keppens, R Schure, K |
| author_sort | Goedbloed, J |
| collection | OXFORD |
| description | It is well known that interchange instabilities (and associated ballooning modes) in laboratory fusion devices limit the maximum value of the plasma due to per-turbations with a wave vector perpendicular, or nearly perpendicular, to the mag-netic field. For those perturbations, the field line bending energy is minimal. The connection between interchange and gravitational (Rayleigh-Taylor) instabilities has frequently been exploited to model the more complicated geometry-dependent dynamics. It is of interest to recall the early work of Newcomb [1] which demon-strated that some of the more subtle gravitational instabilities, the so-called quasiinterchange instabilities, require a small parallel component of the wave vector. However, instability is limited to a range of wave vectors that always have a much smaller component parallel than normal to the field lines. Thus, in laboratory plasma theory, it became a kind of paradigm to assume that all major instabilities operate under these conditions. On the other hand, in astrophysical plasmas like the spiral arms of galaxies, instabilities are operating that produce flow along the magnetic field lines and that require the wave vector to be mainly parallel to the magnetic field: the Parker instabilities [2, 3]. Surprisingly, the apparent contradiction of the astrophysical results and the laboratory prejudice appears to have escaped attention. We here present an attempt to reconcile these approaches by fitting both classes of instabilities, the interchange and Parker instabilities, into a wider spectral framework. In the unified theory, a new kind of instabilities appear that we have termed quasi-Parker instabilities. |
| first_indexed | 2024-03-06T22:57:56Z |
| format | Journal article |
| id | oxford-uuid:61114a23-1fd4-4522-8adc-e4c3399e983f |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:57:56Z |
| publishDate | 2006 |
| record_format | dspace |
| spelling | oxford-uuid:61114a23-1fd4-4522-8adc-e4c3399e983f2022-03-26T17:57:21ZConnection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxiesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:61114a23-1fd4-4522-8adc-e4c3399e983fEnglishSymplectic Elements at Oxford2006Goedbloed, JBlokland, JKeppens, RSchure, KIt is well known that interchange instabilities (and associated ballooning modes) in laboratory fusion devices limit the maximum value of the plasma due to per-turbations with a wave vector perpendicular, or nearly perpendicular, to the mag-netic field. For those perturbations, the field line bending energy is minimal. The connection between interchange and gravitational (Rayleigh-Taylor) instabilities has frequently been exploited to model the more complicated geometry-dependent dynamics. It is of interest to recall the early work of Newcomb [1] which demon-strated that some of the more subtle gravitational instabilities, the so-called quasiinterchange instabilities, require a small parallel component of the wave vector. However, instability is limited to a range of wave vectors that always have a much smaller component parallel than normal to the field lines. Thus, in laboratory plasma theory, it became a kind of paradigm to assume that all major instabilities operate under these conditions. On the other hand, in astrophysical plasmas like the spiral arms of galaxies, instabilities are operating that produce flow along the magnetic field lines and that require the wave vector to be mainly parallel to the magnetic field: the Parker instabilities [2, 3]. Surprisingly, the apparent contradiction of the astrophysical results and the laboratory prejudice appears to have escaped attention. We here present an attempt to reconcile these approaches by fitting both classes of instabilities, the interchange and Parker instabilities, into a wider spectral framework. In the unified theory, a new kind of instabilities appear that we have termed quasi-Parker instabilities. |
| spellingShingle | Goedbloed, J Blokland, J Keppens, R Schure, K Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title | Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title_full | Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title_fullStr | Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title_full_unstemmed | Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title_short | Connection of interchange instabilities in tokamaks and Parker instabilities in spiral arms of galaxies |
| title_sort | connection of interchange instabilities in tokamaks and parker instabilities in spiral arms of galaxies |
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