Constraints on coronal outflow velocities derived from UVCS Doppler dimming measurements and in-situ charge state data

Leonard Strachan, Y. K. Ko, A. V. Panasyuk, D. Dobrzycka, J. L. Kohl, M. Romoli, G. Noci, S. E. Gibson, D. A. Biesecker

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We constrain coronal outflow velocity solutions, resolved along the line-of-sight, by using Doppler dimming models of H I Lyman alpha and O VI 1032/1037 A emissivities obtained with data from the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO. The local emissivities, from heliocentric heights of 1.5 to 3.0 solar radii, were determined from 3-D reconstructions of line-of-sight intensities obtained during the first Whole Sun Month Campaign (10 August to 8 September 1996). The models use electron densities derived from polarized brightness measurements made with the visible light coronagraphs on UVCS and LASCO, supplemented with data from Mark III at NCAR/MLSO. Electron temperature profiles are derived from 'freezing-in' temperatures obtained from an analysis of charge state data from SWICS/Ulysses. The work concentrates on neutral hydrogen outflow velocities which depend on modeling the absolute coronal H I Lyα emissivities. We use an iterative method to determine the neutral hydrogen outflow velocity with consistent values for the electron temperatures derived from a freezing-in model.

Original languageEnglish
Pages (from-to)311-314
Number of pages4
JournalSpace Science Reviews
Volume87
Issue number1-2
DOIs
StatePublished - 1999

Keywords

  • Corona
  • Line profiles
  • Solar wind
  • Spectroscopy
  • UV radiation

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