Self-similar turbulent dynamo.
The amplification of magnetic fields in a highly conducting fluid is studied numerically. During growth, the magnetic field is spatially intermittent: it does not uniformly fill the volume, but is concentrated in long thin folded structures. Contrary to a commonly held view, intermittency of the fol...
| Main Authors: | , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2004
|
| _version_ | 1797088463335456768 |
|---|---|
| author | Schekochihin, A Cowley, S Maron, J McWilliams, J |
| author_facet | Schekochihin, A Cowley, S Maron, J McWilliams, J |
| author_sort | Schekochihin, A |
| collection | OXFORD |
| description | The amplification of magnetic fields in a highly conducting fluid is studied numerically. During growth, the magnetic field is spatially intermittent: it does not uniformly fill the volume, but is concentrated in long thin folded structures. Contrary to a commonly held view, intermittency of the folded field does not increase indefinitely throughout the growth stage if diffusion is present. Instead, as we show, the probability-density function (PDF) of the field-strength becomes self-similar. The normalized moments increase with magnetic Prandtl number in a powerlike fashion. We argue that the self-similarity is to be expected with a finite flow scale and system size. In the nonlinear saturated state, intermittency is reduced and the PDF is exponential. Parallels are noted with self-similar behavior recently observed for passive-scalar mixing and for map dynamos. |
| first_indexed | 2024-03-07T02:50:27Z |
| format | Journal article |
| id | oxford-uuid:ad836cc5-c4c8-45fb-b24c-4d98d40737b1 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:50:27Z |
| publishDate | 2004 |
| record_format | dspace |
| spelling | oxford-uuid:ad836cc5-c4c8-45fb-b24c-4d98d40737b12022-03-27T03:36:01ZSelf-similar turbulent dynamo.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:ad836cc5-c4c8-45fb-b24c-4d98d40737b1EnglishSymplectic Elements at Oxford2004Schekochihin, ACowley, SMaron, JMcWilliams, JThe amplification of magnetic fields in a highly conducting fluid is studied numerically. During growth, the magnetic field is spatially intermittent: it does not uniformly fill the volume, but is concentrated in long thin folded structures. Contrary to a commonly held view, intermittency of the folded field does not increase indefinitely throughout the growth stage if diffusion is present. Instead, as we show, the probability-density function (PDF) of the field-strength becomes self-similar. The normalized moments increase with magnetic Prandtl number in a powerlike fashion. We argue that the self-similarity is to be expected with a finite flow scale and system size. In the nonlinear saturated state, intermittency is reduced and the PDF is exponential. Parallels are noted with self-similar behavior recently observed for passive-scalar mixing and for map dynamos. |
| spellingShingle | Schekochihin, A Cowley, S Maron, J McWilliams, J Self-similar turbulent dynamo. |
| title | Self-similar turbulent dynamo. |
| title_full | Self-similar turbulent dynamo. |
| title_fullStr | Self-similar turbulent dynamo. |
| title_full_unstemmed | Self-similar turbulent dynamo. |
| title_short | Self-similar turbulent dynamo. |
| title_sort | self similar turbulent dynamo |
| work_keys_str_mv | AT schekochihina selfsimilarturbulentdynamo AT cowleys selfsimilarturbulentdynamo AT maronj selfsimilarturbulentdynamo AT mcwilliamsj selfsimilarturbulentdynamo |