Peak flux density spectra of large solar radio bursts and proton emission from flares

Journal Article · Mon Jul 01 04:00:00 EDT 1985 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA090iA07p06251· OSTI ID:5516050

Cliver, E W; McNamara, L F; Gentile, L C

We have reexamined the relationship between ''U-shaped'' peak flux density microwave spectra and solar proton events for approx.200 large (Sp(> or =2 GHz)> or =800 solar flux units (sfu) microwave bursts (1965-1979). The radio spectra fell into two basic classes: U-shaped, with two maxima (> or =800 sfu) in the range from 200 MHz to > or =10 GHz (59% of all events), and cutoff spectra, with a maximum > or =800 sfu at f> or =2 GHz and Sp (200 MHz)<100 sfu (18%). Nine percent of the events had ''intermediate'' spectra with a maximum > or =800 sfu at f> or =2 GHz and 100 sfu < or =Sp (200 MHz)<800 sfu. We were unable to classify 15% of the events because of incomplete data. The associations of the three classes of spectra with type II (and/or type IV) meter wavelength bursts and >10-MeV proton events of any size (> or =0.01 protons cm/sup -2/ s/sup -1/ sr/sup -1/) are as follows: U-shaped: type II/IV (90% of large microwave bursts with U-shaped spectra are associated with type II/IV events), protons (77%); intermediate: type II/IV (78%), protons (73%); and cutoff, type II/IV (22%), protons (33%). These statistics affirm various lines of evidence linking coronal shock waves and interplanetary proton events. They also suggest that the meter wavelength branch of the U-shaped spectrum may be attributable to second-phase (versus flash phase) accelerated electrons.

• Research Organization: Air Force Geophysics Laboratory, Hanscom Air Force Base, Massachusetts
• OSTI ID: 5516050
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 90:A7; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics &amp; Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BARYONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
FERMIONS
FLUX DENSITY
HADRONS
MICROWAVE SPECTRA
NUCLEONS
PROTONS
RADIATIONS
RADIOWAVE RADIATION
SOLAR ACTIVITY
SOLAR FLARES
SOLAR PARTICLES
SOLAR PROTONS
SOLAR RADIATION
SOLAR RADIO BURSTS
SPECTRA
STELLAR RADIATION