High-Resolution Profiles of Gamma-Ray Lines from the X-Class Solar Flare of 23 July, 2002
Abstract
The Reuven Ramaty High Energy Solar Spectroscopy Imager (RHESSI) has produced the first high-resolution measurement of nuclear de-excitation lines in a solar flare. The flare, which occurred on 23 July, 2002, was a GOES X4.8 event at a heliocentric angle of ~ 73 deg. Doppler shifts and broadening are seen in lines of neon, magnesium, silicon, iron, carbon and oxygen. We compare the observed redshifts and widths to simulations with four adjustable parameters: spectral index, alpha/proton ratio, the angle of the line of sight to the magnetic field, and a measure of the pitch angle distribution of the accelerated ions. In all cases, the observed redshifts are greater than would be expected from models of pitch-angle scattering in a loop perpendicular to the solar surface. Either the loop containing the ions in this flare was bent toward the solar surface, or else the ions were strongly beamed along the field.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2003
- Accession Number
- ADA596186
Entities
People
- A. Y. Shih
- D. M. Smith
- Gerald H. Share
- R. A. Schwartz
- R. P. Lin
- Ronald J. Murphy
Organizations
- United States Naval Research Laboratory