Solar wind structure analyzed by tomography of interplanetary scintillation
Abstract
We have analyzed the global structure of the solar wind in the minimum phase of the solar cycle using interplanetary scintillation (IPS) observation data obtained at STE Lab. We examined the relation between the solar wind velocity V and electron density fluctuations delta Ne with CAT analysis, and derived the best fit power-low of delta Ne propto V^{- gamma} with gamma = 0.5 plus or minus 0.15. This result indicates that delta Ne/N in a fast wind is lager than that of slow wind. We have then analyzed IPS speed data during Carrington rotations 1894--1896, which matched the passage of the Ulysses spacecraft of its rapid latitude traversal from southern to northern hemisphere. As the result, we confirmed that high-speed regions with speed of about 800 km/s are separated from an equatorial low-speed region with a sharp velocity gradient at heliographic latitudes of 15circ to 20circ in both hemispheres. This latitudinal variation is agreed with Ulysses observations very well.
- Publication:
-
IAU Joint Discussion
- Pub Date:
- 1997
- Bibcode:
- 1997IAUJD..19E..59Y