A generalized effective potential for differentially rotating plasmas
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866915239290732544 |
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| author | Ebrahimi, Fatima Haywood, Alexander |
| author_facet | Ebrahimi, Fatima Haywood, Alexander |
| contents | Global stability of differentially rotating plasma is investigated using a generalized effective potential. We first, for a current-free system, obtain a general form of an effective potential in terms of the free energies of global curvature and gradients of rotation for non-axisymmetric disturbances. We then examine the stability of differentially rotating disks for several rotation profiles and present the associated effective potential for the onset of these instabilities in the MHD regime. In particular, results for global axisymmetric magnetorotational instability (MRI) as well as local and global non-axisymmetric modes are presented. The latter constitute two distinct non-axisymmetric modes, a high frequency local MRI and a global low-frequency non-axisymmetric mode (the magneto-curvature mode, introduced in Ebrahimi&Pharr, ApJ 2022), confined either between two Alfvénic resonances or an Alfvénic resonance and a boundary. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2412_07742 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | A generalized effective potential for differentially rotating plasmas Ebrahimi, Fatima Haywood, Alexander High Energy Astrophysical Phenomena Plasma Physics Global stability of differentially rotating plasma is investigated using a generalized effective potential. We first, for a current-free system, obtain a general form of an effective potential in terms of the free energies of global curvature and gradients of rotation for non-axisymmetric disturbances. We then examine the stability of differentially rotating disks for several rotation profiles and present the associated effective potential for the onset of these instabilities in the MHD regime. In particular, results for global axisymmetric magnetorotational instability (MRI) as well as local and global non-axisymmetric modes are presented. The latter constitute two distinct non-axisymmetric modes, a high frequency local MRI and a global low-frequency non-axisymmetric mode (the magneto-curvature mode, introduced in Ebrahimi&Pharr, ApJ 2022), confined either between two Alfvénic resonances or an Alfvénic resonance and a boundary. |
| title | A generalized effective potential for differentially rotating plasmas |
| topic | High Energy Astrophysical Phenomena Plasma Physics |
| url | https://arxiv.org/abs/2412.07742 |