Accession Number:

ADA250097

Title:

Evolution of the Solar and Coronal Field Structure: 1976-1991

Descriptive Note:

Corporate Author:

STANFORD UNIV CA CENTER FOR SPACE SCIENCE AND ASTROPHYSICS

Personal Author(s):

Report Date:

1992-01-01

Pagination or Media Count:

10.0

Abstract:

The magnetic field of the Sun determines the structure of the corona and the interplanetary medium. Observations of the solar field made at the Wilcox Solar Observatory at Stanford from 1976 to the present have been used to model the field patterns in the corona, the source of the heliospheric magnetic field. The IMF polarity at Earth can be predicted with about 80 reliability throughout the solar cycle. However, the field in the ecliptic is just one slice of a three-dimensional structure that changes greatly during the solar cycle. Near solar minimum the heliospheric current sheet is confined to the Suns equatorial region. As the polar fields decay and reverse near solar maximum, the geometry of the heliospheric field becomes much more complex. Model coronal fields can also be used to estimate the solar wind velocity, determine the solar origin of interplanetary structures, and predict the out-of-ecliptic component of the IMF at Earth.

Subject Categories:

  • Astrophysics
  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE