Physical Implications of RHESSI Neutron Capture-Line Measurements
Abstract
We report high spectral-resolution measurements of the 2.223 MeV neutron capture-line obtained with the Reuven Ramaty High Energy Spectroscopic Imager from the 2002 July 23 solar are. The time history of this line is affected by both the photospheric the abundance and the angular distribution of the interacting are-accelerated particles producing the neutrons. The measured time history is compared with predicted time histories calculated using a magnetic loop model with a magnetic eld perpendicular to the solar surface at the footpoints. The model includes energy losses due to Coulomb collisions, removal by nuclear reactions magnetic mirroring in the convergent ux tube, and MHD pitch-angle scattering in the corona. This is the first analysis of the neutron-capture line using such a physically-based model. The derived constraints on the interacting angular distribution require that the accelerated particles had to su er pitchangle scattering during their transport through the coronal portion of the loop. The derived photospheric 3He/H ratio was not well-constrained, primarily due to uncertainties associated with the measured nuclear deexcitation-line ux used to represent the neutron-production time pro le.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2003
- Accession Number
- ADA599606
Entities
People
- David M Smith
- Gerald H. Share
- Richard A. Schwartz
- Robert P. Lin
- Ronald J. Murphy
- Xin-min Hua
Organizations
- United States Naval Research Laboratory