What determines the penumbral size and Evershed flow speed?

Na Deng, Toshifumi Shimizu, Debi Prasad Choudhary, Haimin Wang

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Using Hinode SP and G-band observations, we examined the relationship between magnetic field structure and penumbral length as well as Evershed flow speed. The latter two are positively correlated with magnetic inclination angle or horizontal field strength within 1.5 kilogauss, which is in agreement with recent magnetoconvective simulations of Evershed effect. This work thus provides direct observational evidence supporting the magnetoconvection nature of penumbral structure and Evershed flow in the presence of strong and inclined magnetic field.

Original languageEnglish (US)
Title of host publicationThe Physics of Sun and Star Spots
EditorsDebi Prasad Choudhary, Klaus Strassmeier
Number of pages5
StatePublished - Aug 2010

Publication series

NameProceedings of the International Astronomical Union
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


  • Sun: atmospheric motions
  • Sun: magnetic fields
  • Sun: photosphere.
  • Sunspots


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