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Electron Density Measurement in an Active Region observed By Extreme Ultraviolet Imaging Spectrometer (EIS) on Hinode

Author Affiliations

  • 1 Department of Physics, K G K (P G) College, Moradabad 244 001, Uttar Pradesh, INDIA
  • 2 Department of Physics, Hindu College, Moradabad 244 001, Uttar Pradesh, INDIA

Res. J. Recent Sci., Volume 1, Issue (1), Pages 40-45, January,2 (2012)

Abstract

Active regions are the brightest features seen on the Suns surface when observing in ultra-violet and X-rays. They are the structures of complex magnetic topology and most of the high energy explosions such as flares and coronal mass ejections (CMEs) originate from active regions. The Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode provides an excellent opportunity to study the physical plasma parameters in spatially resolved coronal structures. Using spectral observations performed over an active region on February 07, 2007 with the EIS spectrometer on Hinode, we study the density structure at different temperatures. To analyze the density structure we compare density ratios of a series of iron lines Fe XII 186.88 , Fe XII 195.12 , Fe XIII 202.04 , Fe XIII 203.82 , Fe XIV 264.79 and Fe XIV 274.20 observed by the Hinode/EUV Imaging Spectrometer (EIS). We found that the electron density in the observed active region (AR 10940) varies from 10-1012 cm-3 and is highest in the core of this active region.

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