Author: William E. O'Brien Publisher: ISBN: Category : Protons Languages : en Pages : 68
Book Description
The short-term prediction of solar proton events based on a distinct U-shaped radio burst signature is verified. The prediction techniques uses peak flux density values of discrete frequency solar radio burst observations in the 100 to 10,000 MHz region. The criteria are applied to all major proton events from 1952 to 1969 and afford almost total success in predicting near-earth particle events that eminated from visible hemisphere regions of the sun. A correlation between U-shaped radio burst signatures and solar proton events as detected by the ATS-1 satellite, during 1967 and 1968, is also shown to be highly successful. Finally, a 'modified' U-shaped criterion is set forth for the accurate short-terms prediction of polar cap absorption events that result in at least a 2.0 dB riometer measurement of absorption. This 'modified' spectral configuration is then correlated with the major absorption events of the current solar cycle and it is found that prediction occurred for all principal PCA events that originated from visible solar hemisphere flares. (Author).
Author: William E. O'Brien Publisher: ISBN: Category : Protons Languages : en Pages : 0
Book Description
The short-term prediction of solar proton events based on a distinct U-shaped radio burst signature is verified. The prediction technique uses peak flux density values of discrete frequency solar radio burst observations in the 100 to 10,000 MHz region. The criteria are applied to all major proton events from 1952 to 1969 and afford almost total success in predicting near-earth particle events that emanated from visible hemisphere regions of the sun. A correlation between U-shaped radio burst signatures and solar proton events as detected by the ATS-1 satellite, during 1967 and 1968, is also shown to be highly successful. Finally, a 'modified' U-shaped criterion is set forth for the accurate short-term prediction of polar cap absorption events that result in at least a 2.0 dB riometer measurement of absorption. This 'modified' spectral configuration is then correlated with the major absorption events of the current solar cycle and it is found that prediction occurred for all principal PCA events that originated from visible solar hemisphere flares. (Author).
Author: John P. Castelli Publisher: ISBN: Category : Protons Languages : en Pages : 50
Book Description
A catalog of about 118 proton events, 1966-1976, not included in an earlier catalog of 81 events (AFGL TR-77-0081) for the same period is presented. These 118 events combined with the earlier 81 provide the basis for summarizing solar radio burst/high-energy proton correlation and prediction signature work. In the earlier effort, hereafter called Catalog I, the starting point was the identification of all solar radio bursts having the classical U-shape spectrum, and then establishing proton event association for the purpose of devising a reliable 'false-alarm' free predictor of the major proton events (equivalent PCA 2-2. 5dB). In the present effort, the starting point is the identification of all other proton events not included in Catalog I (misses by the U-shape spectrum criteria), and then searching for the establishing solar radio correlations and possible predictions of weaker proton events. There are very few real misses of principal proton events.
Author: Edward W. Cliver Publisher: ISBN: Category : Proton flares Languages : en Pages : 62
Book Description
We have reexamined the relationship between U-shaped peak-flux-density microwave spectra and solar proton events for approx 200 large (Sp(> or = 2GHz) > or = 800 solar flux uits (sfu) microwave burst (1965 - 1979). The radio spectra fell into two basic classes: (a) U-shaped with two maxima ( > or = 800 sfu) in the range from 200 MHz to > or = 10 GHz (59 percent of all events), and (b) cutoff spectra with a maximum > or = 800 sfu at f > or = 2 GHz and Sp (200 MHz) 100 sfu (18 percent). 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 percent of the events because of incomplete data. The associations of the three classes of spectra with Type II (and/or Type IV) meter wavelenght bursts and 10 MeV proton events of any size ( or = 0.01 pr per sq cm per sec per sr) are as follows: U-shaped Type II/IV (90 percent of large microwave bursts with U-shaped spectra are associated with Type II/IV events), protons (77 percent); intermediate Type II/IV (78 percent), protons (73 percent); and cutoff Type II/IV (22 percent), protons (33 percent). 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 (vs flash phase) accelerated electrons.
Author: William R. Barron Publisher: ISBN: Category : Protons Languages : en Pages : 36
Book Description
Time-integrated solar ratio fluxes and their association with satellite observed solar energetic proton flux increases have been studied. The time-integration was only of the U-portion of the radio burst flux increase. The best correlations between the integrated radio fluxes and the proton peak fluxes were realized when the radio fluxes were multiplied by the factor exp (-3B), where B is the angular distance, in radians, between the site of the flare and the solar footpoint of the magnetic field connection between the sun and the earth. The solar footpoint positions were determined from the solar wind speed. Two-variate linear regressions were computed using the time-integrated radio fluxes at five discrete radio frequencies in the 606 to 8800 MHz frequency interval and peak proton fluxes at > 10 MeV and > 30 MeV. The higher frequencies of 2695, 4995 and 8800 MHz all correlated better with the > 10 -MeV protons than the lower frequencies. The > 30-MeV protons were even better correlated with the higher frequencies, but correlation with the lower frequencies were poorer. The Total Energy Density, E sub T, of the radio burst, an integration across the frequency interval of the time-integrated radio fluxes at each frequency, was found to be better correlated with the proton fluxes than any of the individual frequencies.
Author: William E. O'Brien
Author: William E. O'Brien (CAPT, USAF.)
Author: William E. O'Brien
Author: Richard Frank Donnelly
Author: John P. Castelli
Author: Richard Frank Donnelly
Author: Edward W. Cliver
Author: Edward Glenn Howard
Author: William R. Barron
Author: Richard Frank Donnelly