Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission

Details Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission

Dec 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufmsh31a1147n&link_type=abstract

American Geophysical Union, Fall Meeting 2004, abstract #SH31A-1147

Physics

7513 Coronal Mass Ejections, 2100 Interplanetary Physics, 2162 Solar Cycle Variations (7536), 2164 Solar Wind Plasma

Scientific paper

There is a uniform flow of the interplanetary hydrogen in the solar system. The distribution of interplanetary neutral hydrogen is sensitive to solar wind proton flux, which has a latitudinal distribution, because interplanetary neutral hydrogen atoms are mainly ionized through a process of charge-exchange with solar wind protons (contributing to 80% of the total ionization rate). Rucinski et al. [1996] estimated the ionization rate of the interplanetary hydrogen in an average solar activity condition: 6.4±0.14 [10E-7/s] for charge exchange with protons. The most practical technique for determining the latitudinal dependence of the interplanetary hydrogen is observation of resonant backscatter of solar Lyman ƒ¿ emission at 121.6 nm. The interplanetary Lyman ƒ¿ emission has been measured by the ultraviolet imaging spectrometer (UVS) on board the Nozomi spacecraft crusing on its Mars transfer orbit with a periapsis of 1 AU and an apoapsis 1.5 AU from the Sun. The field-of-view of UVS is perpendicular to the spin axis of the spacecraft, which is controlled toward the Earth. The spatial resolution of UVS is 1.41 degrees in a plane perpendicular to the spin axis and 0.29 degrees in a plane including the spin axis. Spatial distributions are obtained from the full sky scanning of UVS with spin and orbital motions of the Nozomi spacecraft. One-year UVS data enable us to construct a full sky image of Lyman ƒ¿ emission. We present the results obtained from Nozomi/UVS data analysis for the period of 1999-2002. From a fitting of model calculations to the observed data, it is confirmed that a latitudinal anisotropy with the higher ionization region at the equator is reduced toward solar maximum. Finally, higher ionization region are found at the poles than at the equator near solar maximum. Basically, this change is produced by variations in the latitudinal dependence of persistent solar wind proton flux. However, proton flux from transient CMEs also affects the distribution of the interplanetary hydrogen. We identify the effect of CMEs on the distribution of interplanetary hydrogen from the analysis of CME data collected by SOHO/LASCO.

Affiliated with

Also associated with

No associations

Rating

Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission 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 Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Latitudinal dependence of solar proton flux derived from interplanetary Lyman alpha emission will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1461464