On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions

Details On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions

May 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005agusmsp33a..02c&link_type=abstract

American Geophysical Union, Spring Meeting 2005, abstract #SP33A-02

Physics

2164 Solar Wind Plasma, 2169 Sources Of The Solar Wind, 7509 Corona, 7511 Coronal Holes, 7549 Ultraviolet Emissions

Scientific paper

We present a reanalysis of UVCS/SOHO observations of the O VI 1032, 1037 emission line doublet at large heliocentric distances in polar coronal holes during the last solar minimum (1996-1997). The traditional interpretation of the broad line widths and unusual intensity ratios has been that the oxygen ions exhibit a strong temperature anisotropy, with the temperature perpendicular to the magnetic field being much larger than the temperature parallel to the field. However, a recent paper by Raouafi and Solanki suggested that it may be possible to model the observations using an isotropic velocity distribution of (still very hot) oxygen ions. In this presentation we show that the standard interpretation of an anisotropic distribution is the only one that is fully consistent with the observational data. Using the same electron density and magnetic field models assumed by Raouafi and Solanki, we varied the 3 main ion properties (outflow speed and the 2 bi-Maxwellian temperature components) in a 3D data-cube that exhaustively treated all possibilities. This data-cube spans the parameter space of both earlier UVCS/SOHO empirical models and the new proposal of Raouafi and Solanki. Even so, we find that above about 2.5 solar radii the only points in the data-cube that reproduce the actual observed line widths and intensity ratios are those with substantial temperature anisotropies.

Affiliated with

Also associated with

No associations

Rating

On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Incompatibility Between UVCS/SOHO Observations of Polar Coronal Holes and Isotropic Oxygen Velocity Distributions will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1698774