Loading...
Please wait, while we are loading the content...
Similar Documents
Solar response to luminosity variations
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Arendt, S. |
| Copyright Year | 1990 |
| Description | The connection between solar luminosity and magnetic fields is now well-established. Magnetic fields under the guise of sunspots and faculae enhance or suppress heat transfer through the solar surface, leading to changes in the total solar luminosity. This raises the question of the effect that such surface heat transfer perturbations have on the internal structure of the sun. The problem has been considered previously by Foukal and Spruit. Here, researchers generalize the calculation of Spruit, removing the assumption of a constant heat diffusivity coefficient by treating the full mixing length heat transfer expression. Further, they treat the surface conditions in a simpler manner, and show that the previous conclusions of Foukal and Spruit are unaffected by these modifications. The model shows that following the application of a step function emissivity change: a fraction 1 - D(sub 0) of the luminosity change relaxes away after approx. 50 days. This corresponds to the thermal diffusion time across the convection zone, adjusting to a value in correspondence with the surface change. In other words, the whole convection zone feels the perturbation on this timescale. The remaining fraction relaxes away on a timescale of 10 to the 5th power years, corresponding to the convective layer radiating away enough energy so that it can adjust to its new adiabat. These are the same results arrived at by Spruit and Foukal. For variations of sigma on timescales of 10 to 200 years, then, the only important relaxation is the 50 day one. If the amplitude of this relaxation is small, the luminosity follows the sigma variation. |
| File Size | 162994 |
| Page Count | 5 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19910003154 |
| Archival Resource Key | ark:/13960/t50g8k59n |
| Language | English |
| Publisher Date | 1990-08-01 |
| Access Restriction | Open |
| Subject Keyword | Solar Physics Thermal Diffusion Mixing Length Flow Theory Faculae Luminosity Variations Perturbation Sun Emissivity Surface Properties Adiabatic Conditions Models Diffusion Coefficient Solar Interior Solar Radiation Sunspots Solar Magnetic Field Heat Transfer Step Functions Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
