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Fitting the AP-8 spectra to determine the proton momentum distribution functions in space radiations

dc.contributor.authorPierrard, V.
dc.contributor.authorBorremans, K.
dc.date2012
dc.date.accessioned2016-03-29T10:07:36Z
dc.date.available2016-03-29T10:07:36Z
dc.identifier.urihttps://orfeo.belnet.be/handle/internal/3003
dc.descriptionThe differential flux J(E) observed in space radiations can be related to the characteristics of the particle momentum distribution functions. In fitting flux spectra by a sum of Maxwellians or by power laws, the slope of the differential flux is associated with the characteristic energy of the distributions and the normalization constant is proportional to the density. The goal of this work is to obtain a density-energy description of the radiation belts by using the kinetic approach. Starting from the proton spectra of the radiation belt models AP-8 MIN and AP-8 MAX, we show that the best fits are given by a power law at 1.8L < 4 while a sum of two Maxwellians give best fits at large radial distances. Assuming the correspondence between the momentum distributions and the observed spectra, we determine the variations of number density and energy with the radial distance, with the latitude and during minimum and maximum solar activity. This analysis provides information on the origin and mechanisms influencing the radiation populations.
dc.languageeng
dc.titleFitting the AP-8 spectra to determine the proton momentum distribution functions in space radiations
dc.typeArticle
dc.subject.frascatiPhysical sciences
dc.audienceScientific
dc.subject.freeAP-8
dc.subject.freeBest fit
dc.subject.freeCharacteristic energy
dc.subject.freeDifferential flux
dc.subject.freeKappa
dc.subject.freeKinetic approach
dc.subject.freeMomentum distribution function
dc.subject.freeMomentum distributions
dc.subject.freeNormalization constants
dc.subject.freeNumber density
dc.subject.freeParticle momentum distribution function
dc.subject.freePower-law
dc.subject.freeProton spectra
dc.subject.freeRadial distance
dc.subject.freeRadiation belt model
dc.subject.freeSolar activity
dc.subject.freeSpace radiations
dc.subject.freeAtmospheric spectra
dc.subject.freeKinetics
dc.subject.freeProtons
dc.subject.freeSolar energy
dc.subject.freeRadiation belts
dc.source.titleRadiation Measurements
dc.source.volume47
dc.source.issue6
dc.source.page401-405
Orfeo.peerreviewedYes
dc.identifier.doi10.1016/j.radmeas.2012.04.002
dc.identifier.scopus2-s2.0-84861938971


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