Interplanetary Lyman $α$ line profiles: variations with solar activity cycle

Details Interplanetary Lyman $α$ line profiles: variations with solar activity cycle Interplanetary Lyman $α$ line profiles: variations with solar activity cycle

2006-09-11

arxiv.org/abs/astro-ph/0609278v1

Astronomy and Astrophysics

Astrophysics

9 pages, 9 figures

Scientific paper

10.1051/0004-6361:20065169

Interplanetary Lyman alpha line profiles are derived from the SWAN H cell data measurements. The measurements cover a 6-year period from solar minimum (1996) to after the solar maximum of 2001. This allows us to study the variations of the line profiles with solar activity. These line profiles were used to derive line shifts and line widths in the interplanetary medium for various angles of the LOS with the interstellar flow direction. The SWAN data results were then compared to an interplanetary background upwind spectrum obtained by STIS/HST in March 2001. We find that the LOS upwind velocity associated with the mean line shift of the IP \lya line varies from 25.7 km/s to 21.4 km/s from solar minimum to solar maximum. Most of this change is linked with variations in the radiation pressure. LOS kinetic temperatures derived from IP line widths do not vary monotonically with the upwind angle of the LOS. This is not compatible with calculations of IP line profiles based on hot model distributions of interplanetary hydrogen. We also find that the line profiles get narrower during solar maximum. The results obtained on the line widths (LOS temperature) show that the IP line is composed of two components scattered by two hydrogen populations with different bulk velocities and temperature. This is a clear signature of the heliospheric interface on the line profiles seen at 1 AU from the sun.

Affiliated with

Also associated with

No associations

Rating

Interplanetary Lyman $α$ line profiles: variations with solar activity cycle 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 Interplanetary Lyman $α$ line profiles: variations with solar activity cycle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Interplanetary Lyman $α$ line profiles: variations with solar activity cycle will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-25079