Oblate electron holes are not attributable to anisotropic shielding
The influence of shielding mechanisms on the ratio of perpendicular to parallel scale lengths of multidimensional plasma electron hole equilibria is analyzed theoretically and computationally. It is shown that the "gyrokinetic"model, invoking perpendicular polarization, is based on a misun...
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| Format: | Article |
| Language: | English |
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AIP Publishing
2021
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| Online Access: | https://hdl.handle.net/1721.1/134358 |
| _version_ | 1826189031323467776 |
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| author | Hutchinson, IH |
| author_facet | Hutchinson, IH |
| author_sort | Hutchinson, IH |
| collection | MIT |
| description | The influence of shielding mechanisms on the ratio of perpendicular to parallel scale lengths of multidimensional plasma electron hole equilibria is analyzed theoretically and computationally. It is shown that the "gyrokinetic"model, invoking perpendicular polarization, is based on a misunderstanding and cannot explain the observational trend that greater transverse extent accompanies a lower magnetic field. Instead, the potential in the wings of the hole, outside the region of trapped-electron depletion, has isotropic shielding giving φ ∝ e - r / L / r, with the shielding length L equal to the Debye length for holes much slower than the electron thermal speed. Particle in cell simulations confirm the analysis. Trapped electron charge distribution anisotropy must, therefore, instead underlie the oblate shape of electron holes. |
| first_indexed | 2024-09-23T08:08:29Z |
| format | Article |
| id | mit-1721.1/134358 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T08:08:29Z |
| publishDate | 2021 |
| publisher | AIP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/1343582021-10-28T05:02:38Z Oblate electron holes are not attributable to anisotropic shielding Hutchinson, IH The influence of shielding mechanisms on the ratio of perpendicular to parallel scale lengths of multidimensional plasma electron hole equilibria is analyzed theoretically and computationally. It is shown that the "gyrokinetic"model, invoking perpendicular polarization, is based on a misunderstanding and cannot explain the observational trend that greater transverse extent accompanies a lower magnetic field. Instead, the potential in the wings of the hole, outside the region of trapped-electron depletion, has isotropic shielding giving φ ∝ e - r / L / r, with the shielding length L equal to the Debye length for holes much slower than the electron thermal speed. Particle in cell simulations confirm the analysis. Trapped electron charge distribution anisotropy must, therefore, instead underlie the oblate shape of electron holes. 2021-10-27T20:04:36Z 2021-10-27T20:04:36Z 2021 2021-08-10T15:01:38Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/134358 en 10.1063/5.0039233 Physics of Plasmas Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf AIP Publishing arXiv |
| spellingShingle | Hutchinson, IH Oblate electron holes are not attributable to anisotropic shielding |
| title | Oblate electron holes are not attributable to anisotropic shielding |
| title_full | Oblate electron holes are not attributable to anisotropic shielding |
| title_fullStr | Oblate electron holes are not attributable to anisotropic shielding |
| title_full_unstemmed | Oblate electron holes are not attributable to anisotropic shielding |
| title_short | Oblate electron holes are not attributable to anisotropic shielding |
| title_sort | oblate electron holes are not attributable to anisotropic shielding |
| url | https://hdl.handle.net/1721.1/134358 |
| work_keys_str_mv | AT hutchinsonih oblateelectronholesarenotattributabletoanisotropicshielding |