Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods

Abstract We present a method to determine energy‐dependent geometric factors for charged particle instruments in electron energy range of 125–2,200 keV aboard the geostationary satellite GEO‐KOMPSAT‐2A (GK2A), stationed at 128.2°E longitude. As deduced from the GEANT4 Monte Carlo simulation, the res...

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Main Authors: W.‐H. Seol, C.‐H. Lee, J. Seon, Y.‐C. Shin, K.‐H. Kim, D. E. Larson, G. K. Parks, J. Sample
Format: Article
Language:English
Published: Wiley 2023-01-01
Series:Space Weather
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Online Access:https://doi.org/10.1029/2022SW003265
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author W.‐H. Seol
C.‐H. Lee
J. Seon
Y.‐C. Shin
K.‐H. Kim
D. E. Larson
G. K. Parks
J. Sample
author_facet W.‐H. Seol
C.‐H. Lee
J. Seon
Y.‐C. Shin
K.‐H. Kim
D. E. Larson
G. K. Parks
J. Sample
author_sort W.‐H. Seol
collection DOAJ
description Abstract We present a method to determine energy‐dependent geometric factors for charged particle instruments in electron energy range of 125–2,200 keV aboard the geostationary satellite GEO‐KOMPSAT‐2A (GK2A), stationed at 128.2°E longitude. As deduced from the GEANT4 Monte Carlo simulation, the response function of the instrument in a matrix form was employed to undertake forward‐fitting of the differential energy spectra against various functions such as the double Maxwellian (DM), relativistic kappa (KP), and power‐law (PL). Thereby, we determined the energy‐dependent geometric factors for each energy channel and instrument. The forward‐fitting method was performed for a selected period of geomagnetically quiet days from May to November 2019, by applying stringent conditions to geomagnetic indices and the residual from the fit. It was found that the KP and DM functions provided better fits overall, whereas the PL function yielded considerably worse fits to the measurements. For the KP and DM functions, the validity of the geometric factors was examined against the distributions of the measured count rates and inferred model fluxes. The estimated model parameters, such as the spectral index from the KP function or the temperature from the DM functions, were also analyzed. The present study shows that the instruments provided quantitative observations of the outer radiation belt at a vantage point of 128.2°E longitude and allowed for a simple and reliable means to obtain electron fluxes based on combinations of results from numerical simulation, ground calibration, and space measurements.
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spelling doaj-art-1bedf4751d7642d88c0bcca93f8cb8c92025-01-14T16:35:23ZengWileySpace Weather1542-73902023-01-01211n/an/a10.1029/2022SW003265Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet PeriodsW.‐H. Seol0C.‐H. Lee1J. Seon2Y.‐C. Shin3K.‐H. Kim4D. E. Larson5G. K. Parks6J. Sample7School of Space Research Kyung Hee University Yongin South KoreaSchool of Space Research Kyung Hee University Yongin South KoreaSchool of Space Research Kyung Hee University Yongin South KoreaSatrec Initiative (SI) Daejeon South KoreaSchool of Space Research Kyung Hee University Yongin South KoreaSpace Science Laboratory University of California, Berkeley Berkeley CA USASpace Science Laboratory University of California, Berkeley Berkeley CA USADepartment of Physics Montana State University Bozeman MT USAAbstract We present a method to determine energy‐dependent geometric factors for charged particle instruments in electron energy range of 125–2,200 keV aboard the geostationary satellite GEO‐KOMPSAT‐2A (GK2A), stationed at 128.2°E longitude. As deduced from the GEANT4 Monte Carlo simulation, the response function of the instrument in a matrix form was employed to undertake forward‐fitting of the differential energy spectra against various functions such as the double Maxwellian (DM), relativistic kappa (KP), and power‐law (PL). Thereby, we determined the energy‐dependent geometric factors for each energy channel and instrument. The forward‐fitting method was performed for a selected period of geomagnetically quiet days from May to November 2019, by applying stringent conditions to geomagnetic indices and the residual from the fit. It was found that the KP and DM functions provided better fits overall, whereas the PL function yielded considerably worse fits to the measurements. For the KP and DM functions, the validity of the geometric factors was examined against the distributions of the measured count rates and inferred model fluxes. The estimated model parameters, such as the spectral index from the KP function or the temperature from the DM functions, were also analyzed. The present study shows that the instruments provided quantitative observations of the outer radiation belt at a vantage point of 128.2°E longitude and allowed for a simple and reliable means to obtain electron fluxes based on combinations of results from numerical simulation, ground calibration, and space measurements.https://doi.org/10.1029/2022SW003265outer radiation beltgeostationary orbitgeometric factor
spellingShingle W.‐H. Seol
C.‐H. Lee
J. Seon
Y.‐C. Shin
K.‐H. Kim
D. E. Larson
G. K. Parks
J. Sample
Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
Space Weather
outer radiation belt
geostationary orbit
geometric factor
title Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
title_full Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
title_fullStr Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
title_full_unstemmed Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
title_short Estimation of Geometric Factors for the Particle Detecting Instruments of the Geostationary Satellite GK2A at 128.2°E Longitude Based on Observations of the Outer Radiation Belt During Geomagnetically Quiet Periods
title_sort estimation of geometric factors for the particle detecting instruments of the geostationary satellite gk2a at 128 2°e longitude based on observations of the outer radiation belt during geomagnetically quiet periods
topic outer radiation belt
geostationary orbit
geometric factor
url https://doi.org/10.1029/2022SW003265
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