High Resolution Solar Radio Activity Investigations.
Abstract
The study of cm-mm wavelength radio emission from solar active regions to find flare/proton flare predictors was the task of AFGL's In-House Work Unit 46430302, High Resolution Solar Activity Investigations. Using mapping data from several large radio telescopes, the multi-wavelength active region data was evaluated for significant prediction parameters. A statistical examination of 681 solar-region measurements obtained at wavelengths of 9.1 cm (Stanford), 8 mm (AFCRL), and 3 mm (Aerospace) from 1968 to 1970 was made and related to 25 proton events. Of the 21 different correlation parameters evaluated, the apparent 3-mm flux density, particularly when it exceeded 10 s.f.u., provided the best indication that a region would produce a proton flare. Results of the 21 August 1975 proton-flare observations using the 120-ft Haystack radiotelescope at 3.8 cm are discussed. The solar region involved had a low, and decreasing, brightness temperature before it flared, and not the polarization variations often seen prior to flares. The noise power spectrum analysis of active-region temperature and polarization variations is described. A significant power component was found at 43 mHz (23 sec period) in preflare polarization variations; no such component was found for preflare temperature. Recommendations for future areas of investigation using high-resolution solar radio instrumentation are suggested. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 08, 1977
- Accession Number
- ADA053167
Entities
People
- Ronald M. Straka
Organizations
- Air Force Research Laboratory