The Green Line Corona and Its Relation to the Photospheric Magnetic Field
| Autor: | Dennis G. Socker, Y.-M. Wang, Scott H. Hawley, N. E. Moulton, Rainer Schwenn, Clarence M. Korendyke, Guenter E. Brueckner, N. R. Sheeley, Russell A. Howard, J. R. Kraemer, D. J. Michels |
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| Rok vydání: | 1997 |
| Předmět: |
Physics
Field (physics) Astrophysics::High Energy Astrophysical Phenomena Coronal hole Flux Astronomy and Astrophysics Field strength Coronal loop Astrophysics Coronal radiative losses Corona Nanoflares Space and Planetary Science Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | The Astrophysical Journal. 485:419-429 |
| ISSN: | 1538-4357 0004-637X |
| DOI: | 10.1086/304405 |
| Popis: | Images of the green line corona made with the LASCO C1 coronagraph on SOHO are analyzed by applying current-free extrapolations to the observed photospheric field. The Fe XIV λ5303 emission is shown to be closely related to the underlying photospheric field strength. By modeling the observed intensity patterns as a function of latitude and height above the solar limb, we derive an approximate scaling law of the form nfoot ∝ Bfoot0.9, where nfoot is the density of the green line-emitting plasma and Bfoot is the average field strength at the footprints of the coronal loop. The observed high-latitude enhancements in the green line corona are attributed to the poleward concentration of the large-scale photospheric field. The strongest such enhancements occur where the high-latitude unipolar fields become reconnected to active region flux at lower latitudes; the global emission pattern rotates quasi-rigidly at the rate of the dominant active region complex. The validity of the current-free approximation is assessed by comparing the topology of the observed and simulated green line structures. |
| Databáze: | OpenAIRE |
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