TY - JOUR

T1 - Study of Substorm-Related Auroral Absorption

T2 - Latitudinal Width and Factors Affecting the Peak Intensity of Energetic Electron Precipitation

AU - Nikolaev , A.V.

AU - Sergeev, V. A.

AU - Shukhtina, M. A.

AU - Spanswick, E.

AU - Rogov, D. D.

AU - Stepanov, N. A.

N1 - Funding Information: This research was supported by the Russian Fund for Basic Research Grant 19‐05‐00072. Funding Information: Canadian riometers data are available from the University of Calgary Space Physics Data portal https://data-portal.phys.ucalgary.ca/go_rio/ . The authors gratefully acknowledge the SuperMAG team and collaborators for SML indices and substorm lists used in this study, which are available at http://supermag.jhuapl.edu/ . UofC Space Physics Data Portal activity is undertaken with the financial support of the Canadian Space Agency. The authors thank the national institutes that support them and INTERMAGNET for promoting high standards of magnetic observatory practice www.intermagnet.org . Solar Wind data available from OMNIWeb at https://omniweb.gsfc.nasa.gov/ Publisher Copyright: © 2021. American Geophysical Union. All Rights Reserved.

PY - 2021/12

Y1 - 2021/12

N2 - Previously, suggesting a scenario of “injected and drifting electron cloud” to describe the enhancements and precipitations of energetic electrons during substorms we used the linear prediction filter (LPF) method to build the empirical dynamical model of auroral absorption in the middle of auroral zone, driven by the midlatitude positive bay (MPB) index time series. In this paper, to understand better the relationship between magnetic dipolarization, injection, and energetic electron precipitation, we quantitatively explore correlations between dipolarization proxies (MPB and SML indices, substorm current wedge (SCW) intensity, location, and size) and precipitation-related auroral absorption in the morning maximum region for 148 isolated substorms. We confirm good correlation of precipitation peak values with dipolarization proxies and show that the absorption amplitude is most strongly controlled by total SCW current and its azimuthal size, and is also influenced by solar wind-dependent background energetic electron flux in the conjugate plasma sheet. This result confirms the adequacy of our starting assumption that there is a close relationship between the intensities and size of substorm dipolarizations and energetic particle injections. To extend the latitudinal coverage, we computed the LPF response functions for individual riometers of NORSTAR array. Finding similar shapes and amplitudes of their response at latitudes 63°–69° in the regions where maximal precipitation is statistically observed, we suggest, test, and approve that the auroral absorption in the belt 63°–69° may be predicted using a set of LPFs determined empirically in the center of auroral zone for various magnetic local times.

AB - Previously, suggesting a scenario of “injected and drifting electron cloud” to describe the enhancements and precipitations of energetic electrons during substorms we used the linear prediction filter (LPF) method to build the empirical dynamical model of auroral absorption in the middle of auroral zone, driven by the midlatitude positive bay (MPB) index time series. In this paper, to understand better the relationship between magnetic dipolarization, injection, and energetic electron precipitation, we quantitatively explore correlations between dipolarization proxies (MPB and SML indices, substorm current wedge (SCW) intensity, location, and size) and precipitation-related auroral absorption in the morning maximum region for 148 isolated substorms. We confirm good correlation of precipitation peak values with dipolarization proxies and show that the absorption amplitude is most strongly controlled by total SCW current and its azimuthal size, and is also influenced by solar wind-dependent background energetic electron flux in the conjugate plasma sheet. This result confirms the adequacy of our starting assumption that there is a close relationship between the intensities and size of substorm dipolarizations and energetic particle injections. To extend the latitudinal coverage, we computed the LPF response functions for individual riometers of NORSTAR array. Finding similar shapes and amplitudes of their response at latitudes 63°–69° in the regions where maximal precipitation is statistically observed, we suggest, test, and approve that the auroral absorption in the belt 63°–69° may be predicted using a set of LPFs determined empirically in the center of auroral zone for various magnetic local times.

KW - auroral radiowave absorption

KW - dipolarizations

KW - energetic electron precipitation

KW - energetic particle injections

KW - substorm current wedge

KW - substorms

UR - http://www.scopus.com/inward/record.url?scp=85121805551&partnerID=8YFLogxK

U2 - 10.1029/2021JA029779

DO - 10.1029/2021JA029779

M3 - статья

AN - SCOPUS:85121805551

VL - 126

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9380

IS - 12

M1 - e2021JA029779

ER -