Solar Nebula Magnetohydrodynamics
The dynamical state of the solar nebula depends critically upon whether or not the gas is magnetically coupled. The presence of a subthermal field will cause laminar flow to break down into turbulence. Magnetic coupling, in turn, depends upon the ionization fraction of the gas. The inner most region...
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| Format: | Conference item |
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1999
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| _version_ | 1797075697407098880 |
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| author | Balbus, S Hawley, J |
| author_facet | Balbus, S Hawley, J |
| author_sort | Balbus, S |
| collection | OXFORD |
| description | The dynamical state of the solar nebula depends critically upon whether or not the gas is magnetically coupled. The presence of a subthermal field will cause laminar flow to break down into turbulence. Magnetic coupling, in turn, depends upon the ionization fraction of the gas. The inner most region of the nebula ($\lesssim 0.1$ AU) is magnetically well-coupled, as is the outermost region ($\gtrsim 10$ AU). The magnetic status of intermediate scales ($\sim 1$ AU) is less certain. It is plausible that there is a zone adjacent to the inner disk in which turbulent heating self-consistently maintains the requisite ionization levels. But the region adjacent to the active outer disk is likely to be magnetically ``dead.'' Hall currents play a significant role in nebular magnetohydrodynamics. Though still occasionally argued in the literature, there is simply no evidence to support the once standard claim that differential rotation in a Keplerian disk is prone to break down into shear turbulence by nonlinear instabilities. There is abundant evidence---numerical, experimental, and analytic---in support of the stabilizing role of Coriolis forces. Hydrodynamical turbulence is almost certainly not a source of enhanced turbulence in the solar nebula, or in any other astrophysical accretion disk. |
| first_indexed | 2024-03-06T23:53:55Z |
| format | Conference item |
| id | oxford-uuid:738e975c-80af-40d8-9c91-100d6cd2aecc |
| institution | University of Oxford |
| last_indexed | 2024-03-06T23:53:55Z |
| publishDate | 1999 |
| record_format | dspace |
| spelling | oxford-uuid:738e975c-80af-40d8-9c91-100d6cd2aecc2022-03-26T19:57:11ZSolar Nebula MagnetohydrodynamicsConference itemhttp://purl.org/coar/resource_type/c_5794uuid:738e975c-80af-40d8-9c91-100d6cd2aeccSymplectic Elements at Oxford1999Balbus, SHawley, JThe dynamical state of the solar nebula depends critically upon whether or not the gas is magnetically coupled. The presence of a subthermal field will cause laminar flow to break down into turbulence. Magnetic coupling, in turn, depends upon the ionization fraction of the gas. The inner most region of the nebula ($\lesssim 0.1$ AU) is magnetically well-coupled, as is the outermost region ($\gtrsim 10$ AU). The magnetic status of intermediate scales ($\sim 1$ AU) is less certain. It is plausible that there is a zone adjacent to the inner disk in which turbulent heating self-consistently maintains the requisite ionization levels. But the region adjacent to the active outer disk is likely to be magnetically ``dead.'' Hall currents play a significant role in nebular magnetohydrodynamics. Though still occasionally argued in the literature, there is simply no evidence to support the once standard claim that differential rotation in a Keplerian disk is prone to break down into shear turbulence by nonlinear instabilities. There is abundant evidence---numerical, experimental, and analytic---in support of the stabilizing role of Coriolis forces. Hydrodynamical turbulence is almost certainly not a source of enhanced turbulence in the solar nebula, or in any other astrophysical accretion disk. |
| spellingShingle | Balbus, S Hawley, J Solar Nebula Magnetohydrodynamics |
| title | Solar Nebula Magnetohydrodynamics |
| title_full | Solar Nebula Magnetohydrodynamics |
| title_fullStr | Solar Nebula Magnetohydrodynamics |
| title_full_unstemmed | Solar Nebula Magnetohydrodynamics |
| title_short | Solar Nebula Magnetohydrodynamics |
| title_sort | solar nebula magnetohydrodynamics |
| work_keys_str_mv | AT balbuss solarnebulamagnetohydrodynamics AT hawleyj solarnebulamagnetohydrodynamics |