TY - CONF

T1 - Relationship between dipolarizations and Energetic Electron injections at the Geosynchronous orbit

AU - Шухтина, Мария Алексеевна

AU - Сергеев, Виктор Андреевич

AU - Николаев, Александр Валерьевич

AU - Степанов, Никита

N1 - Conference code: 15

PY - 2024

Y1 - 2024

N2 - Energetic Electron (EE) injections at the geostationary orbit have been studied since the beginning of space era,and very soon their relationship with magnetic dipolarizations was established. It is also well known that particlesintrude into the inner magnetosphere on the nightside, creating non-dispersed injections in the Substorm CurrentWedge (SCW) region, and then drift azimuthally with their own drift speed, forming dispersed injections. EEinjections are an important source of the outer radiation belt, they affect the spacecraft equipment, the radiocommunication and, more globally, the space weather. Betatron/Fermi acceleration during dipolarization areconsidered as the main acceleration mechanisms, but this point still is not well studied.The aim of our work is to study the relationship between injections and dipolarizations inside and outside the SCWbased on joint particle and magnetic data of GOES 13, 14, 15 spacecraft, each pair separated by 2 hours MLT. Weselected clear dipolarizations at the most westward GOES 15 when it was in the pre-midnight sector, and studiedthe EE reaction at GOES 15 itself and at two other more eastward spacecraft. 45 events with data available for atleast two spacecraft, GOES 13 and GOES 15, were considered. Good correlation of the dipolarization magnitude atGOES 15 with increment of substorm MPB index shows that GOES 15 was in the BBF stopping region.In our study we used the EE fluxes dependence on the local magnetic field (hodogram) technique. It showed that1) inside the SCW EE fluxes grow with Bz whereas outside the current wedge these fluxes are independent of localBz, giving the opportunity to separate data inside and outside the injection region. 2) EE dynamics is the result oftwo processes: injections and drift shell crossing. Injections occur on some background level, characteristic for thegiven Bz value, and this level depends on the past geomagnetic activity; 3) on the geostationary orbit the injectionprocess is effective mostly for electrons with energy<200 keV (was known before), for higher energies drift shellcrossing prevails.Our analysis showed that correlations of (ΔMPB) with the peak EE fluxes at energies 30-200 keV is higher thanwith increment of these fluxes, pointing that during the injection a new particle population comes. However, thesecorrelations are also rather low, ≤0.6. Also we demonstrate that (ΔMPB) growth mostly increases the fluxes of electrons in the range 50-100 keV.

AB - Energetic Electron (EE) injections at the geostationary orbit have been studied since the beginning of space era,and very soon their relationship with magnetic dipolarizations was established. It is also well known that particlesintrude into the inner magnetosphere on the nightside, creating non-dispersed injections in the Substorm CurrentWedge (SCW) region, and then drift azimuthally with their own drift speed, forming dispersed injections. EEinjections are an important source of the outer radiation belt, they affect the spacecraft equipment, the radiocommunication and, more globally, the space weather. Betatron/Fermi acceleration during dipolarization areconsidered as the main acceleration mechanisms, but this point still is not well studied.The aim of our work is to study the relationship between injections and dipolarizations inside and outside the SCWbased on joint particle and magnetic data of GOES 13, 14, 15 spacecraft, each pair separated by 2 hours MLT. Weselected clear dipolarizations at the most westward GOES 15 when it was in the pre-midnight sector, and studiedthe EE reaction at GOES 15 itself and at two other more eastward spacecraft. 45 events with data available for atleast two spacecraft, GOES 13 and GOES 15, were considered. Good correlation of the dipolarization magnitude atGOES 15 with increment of substorm MPB index shows that GOES 15 was in the BBF stopping region.In our study we used the EE fluxes dependence on the local magnetic field (hodogram) technique. It showed that1) inside the SCW EE fluxes grow with Bz whereas outside the current wedge these fluxes are independent of localBz, giving the opportunity to separate data inside and outside the injection region. 2) EE dynamics is the result oftwo processes: injections and drift shell crossing. Injections occur on some background level, characteristic for thegiven Bz value, and this level depends on the past geomagnetic activity; 3) on the geostationary orbit the injectionprocess is effective mostly for electrons with energy<200 keV (was known before), for higher energies drift shellcrossing prevails.Our analysis showed that correlations of (ΔMPB) with the peak EE fluxes at energies 30-200 keV is higher thanwith increment of these fluxes, pointing that during the injection a new particle population comes. However, thesecorrelations are also rather low, ≤0.6. Also we demonstrate that (ΔMPB) growth mostly increases the fluxes of electrons in the range 50-100 keV.

KW - инжекция

KW - диполизация

KW - суббуря

KW - энергичные частицы

UR - https://equinocs.springernature.com/service/ics

M3 - Abstract

SP - 207

EP - 207

Y2 - 22 April 2024 through 26 April 2024

ER -