Geodesic
Modeling of anisotropy dynamics of the proton pitch angle distribution in the Earth's magnetosphere
Žurnal Sibirskogo federalʹnogo universiteta. Matematika i fizika, Tome 14 (2021) no. 5, pp. 632-637.

Voir la notice de l'article provenant de la source Math-Net.Ru

Last years the attention to research of anisotropy of the charged particle pitch angle distribution has considerably increased. Therefore for research of anisotropy dynamics of the proton pitch angle distribution is used the two-dimensional Phenomenological Model of the Ring Current (PheMRC 2-D), which includes the radial and pitch angle diffusions with consideration of losses due to wave-particle interactions. Experimental data are collected on the Polar/MICS satellite during the magnetic storm on October 21–22, 1999. Solving the non-stationary two-dimensional equation of pitch angle and radial diffusions, numerically was determined the proton pitch angle distribution anisotropy index (or parameter of the proton pitch angle distribution) for the pitch angle of $90$ degrees during the magnetic storm, when the geomagnetic activity $Kp$-index changed from $2$ in the beginning of a storm up to $7+$ in the end of a storm. Dependence of the perpendicular proton pitch angle distribution anisotropy index with energy $E = 90$ keV during the different moments of time from the McIlwain parameter $L$ ($2.26 L 6.6$) is received. It is certain at a quantitative level for the magnetic storm on October 21–22, 1999, when and where on the nightside of the Earth's magnetosphere ($\mathrm{MLT} = 2300$) to increase in the geomagnetic activity $Kp$-index there is a transition from normal (pancake) proton pitch angle distributions to butterfly proton pitch angle distributions. That has allowed to determine unequivocally and precisely the anisotropy dynamics of the proton pitch angle distribution in the given concrete case. It is shown, that with increase of the geomagnetic activity $Kp$-index the boundary of isotropic proton pitch angle distribution comes nearer to the Earth, reaching $L \thickapprox 3.6$ at $Kp = 7+$.
Keywords: magnetosphere, pitch angle distribution, anisotropy, data of the Polar/MICS satellite
Mots-clés : proton flux. 
@article{JSFU_2021_14_5_a10,
     author = {Sergei V. Smolin},
     title = {Modeling of anisotropy dynamics of the proton pitch angle distribution in the {Earth's} magnetosphere},
     journal = {\v{Z}urnal Sibirskogo federalʹnogo universiteta. Matematika i fizika},
     pages = {632--637},
     publisher = {mathdoc},
     volume = {14},
     number = {5},
     year = {2021},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JSFU_2021_14_5_a10/}
}
TY  - JOUR
AU  - Sergei V. Smolin
TI  - Modeling of anisotropy dynamics of the proton pitch angle distribution in the Earth's magnetosphere
JO  - Žurnal Sibirskogo federalʹnogo universiteta. Matematika i fizika
PY  - 2021
SP  - 632
EP  - 637
VL  - 14
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/JSFU_2021_14_5_a10/
LA  - en
ID  - JSFU_2021_14_5_a10
ER  - 
%0 Journal Article
%A Sergei V. Smolin
%T Modeling of anisotropy dynamics of the proton pitch angle distribution in the Earth's magnetosphere
%J Žurnal Sibirskogo federalʹnogo universiteta. Matematika i fizika
%D 2021
%P 632-637
%V 14
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/JSFU_2021_14_5_a10/
%G en
%F JSFU_2021_14_5_a10
Sergei V. Smolin. Modeling of anisotropy dynamics of the proton pitch angle distribution in the Earth's magnetosphere. Žurnal Sibirskogo federalʹnogo universiteta. Matematika i fizika, Tome 14 (2021) no. 5, pp. 632-637. http://geodesic.mathdoc.fr/item/JSFU_2021_14_5_a10/

[1] S.V. Smolin, “Modeling of pitch angle distribution on the dayside of the Earth's magnetosphere”, Journal of Siberian Federal University. Mathematics $\$ Physics, 5:2 (2012), 269–275 (in Russian) | Zbl

[2] S.V. Smolin, “Modeling the pitch angle distribution on the nightside of the Earth's magnetosphere”, Geomagnetism and Aeronomy, 55:2 (2015), 166–173 | DOI

[3] S.V. Smolin, “Two-dimensional phenomenological model of ring current dynamics in the Earth's magnetosphere”, Geomagnetism and Aeronomy, 59:1 (2019), 27–34 | DOI

[4] X. Gu, Z. Zhao, B. Ni, Y. Shprits, C. Zhou, “Statistical analysis of pitch angle distribution of radiation belt energetic electrons near the geostationary orbit: CRRES observations”, J. Geophys. Res., 116:2011, A01208 | DOI

[5] J.E. Borovsky, M.H. Denton, “A survey of the anisotropy of the outer electron radiation belt during high-speed-stream-driven storms”, J. Geophys. Res., 116:2011, A05201 | DOI

[6] Y. Chen, R.H.W. Friedel, M.G. Henderson, S.G. Claudepierre, S.K. Morley, H. Spence, “REPAD: An empirical model of pitch angle distributions for energetic electrons in the Earth's outer radiation belt”, J. Geophys. Res., 119 (2014), 1693–1708 | DOI

[7] J.E. Borovsky, R.H.W. Friedel, M.H. Denton, “Statistically measuring the amount of pitch angle scattering that energetic electrons undergo as they drift across the plasmaspheric drainage plume at geosynchronous orbit”, J. Geophys. Res., 119 (2014), 1814–1826 | DOI

[8] J.E. Borovsky, T.E. Cayton, M.H. Denton, R.D. Belian, R.A. Christensen, J.C. Ingraham, “The proton and electron radiation belts at geosynchronous orbit: Statistics and behavior during high-speed stream-driven storms”, J. Geophys. Res., 121 (2016), 5449–5488 | DOI

[9] L.M. Kistler, C.G. Mouikis, “The inner magnetosphere ion composition and local time distribution over a solar cycle”, J. Geophys. Res., 121 (2016), 2009–2032 | DOI

[10] H. Zhao, R.H.W. Friedel, Y. Chen, G.D. Reeves, D.N. Baker, X. Li, et al., “An empirical model of radiation belt electron pitch angle distributions based on Van Allen probes measurements”, J. Geophys. Res., 123 (2018), 3493–3511 | DOI

[11] Y. Ebihara, M.-C. Fok, J.B. Blake, J.F. Fennell, “Magnetic coupling of the ring current and the radiation belt”, J. Geophys. Res., 113 (2008), A07221 | DOI