HEPD on NEXTSat-1: A High Energy Particle Detector for Measurements of Precipitating Radiation Belt Electrons

Sohn, Jin-Hun; Lee, Jaejin; Kang, Min; Lee, Junchan; Lee, Seunguk; Lee, Dae-Young; Jo, Gyeongbok; Yi, Yu; Na, Gowoon; Kang, Kyung-In; Shin, Goo-Hwan

doi:10.3938/jkps.72.1086

Cited by 6 publications

(3 citation statements)

References 33 publications

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“…The main payload is the Near-infrared Imaging Spectrometer for Star formation history (NISS), which takes images of the universe in the near-infrared spectral range (Jeong et al, 2014). The secondary payload, the Instrument for the Study of Space Storms (ISSS), provides information on highenergy particles (Seo et al, 2015(Seo et al, , 2021Sohn et al, 2018) and parameters of background cold ionospheric plasma (Lee et al, 2018). The ISSS data are supplemented by a navigation-grade Flux-Gate Magnetometer (FGM), which can continuously measure magnetic field vectors (Song et al, 2021).…”

Section: Accepted Articlementioning

confidence: 99%

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

et al. 2021

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Monitoring the Earth's radiation belt by Low-Earth-Orbit (LEO) satellites has a long history and complemented observations near the high-altitude equatorial plane. However, most of the previous LEO missions suffered from limitations in energy resolution, energy range, L-shell coverage, or the mission lifetime, which leave room for further improvement in this topic. Here we present multi-year (January 2019~February 2021) observations of energetic (0.03 MeV~1.8 MeV) electrons by the Korean NextSat-1 (altitude~575 km) with high energy resolution (0.006-0.4 MeV) and seamless L-shell coverage. For <80 keV electrons, the slot-region outer edge moves inward with increasing geomagnetic activity, which agrees with previous Van Allen Probes reports. The behavior is more conspicuous for lower-energy electrons. Latitudinal profiles of outer-belt electron flux are smoother equatorward of the geosynchronous footprint latitudes (|MLAT|~66 o ) than poleward. The NextSat-1 electron flux is positively correlated to geosynchronous observations, with the coefficient generally higher for higher electron energies. Also, both the geosynchronous and NextSat-1 data exhibit similar spectral indices close to -3 in the log-log space. All these results complement and expand previous knowledge on energetic electrons. The main findings are discussed in the context of existing literature.

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Section: Accepted Articlementioning

confidence: 99%

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

et al. 2021

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“…The ISSS instrument is composed of Space Radiation Detectors (SRDs) and Space Plasma Detectors (SPDs). The SRDs comprise the Medium-Energy Particle Detector (MEPD) and High-Energy Particle Detector (HEPD), and the SPDs comprise the Langmuir Probe (LP), Retarding Potential Analyzer (RPA), and Ion Drift Meter (IDM) (See Sohn et al (2018) and for details of the ISSS instruments). We do not deal with the data from SPDs here, the details of which are described in Choi et al (2014) and Lee et al (2018).…”

Section: Introductionmentioning

confidence: 99%

A Substorm Injection Event and the Radiation Belt Structure Observed by Space Radiation Detectors onboard Next Generation Small Satellite-1 (NEXTSat-1)

Yoo¹,

Lee²,

Kim³

et al. 2021

Journal of Astronomy and Space Sciences

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In this paper, we present observations of the Space Radiation Detectors (SRDs) onboard the Next Generation Small Satellite-1 (NEXTSat-1) satellite. The SRDs, which are a part of the Instruments for the study of Stable/Storm-time Space (ISSS), consist of the Medium-Energy Particle Detector (MEPD) and the High-Energy Particle Detector (HEPD). The MEPD can detect electrons, ions, and neutrals with energies ranging from 20 to 400 keV, and the HEPD can detect electrons over an energy range from 0.35 to 2 MeV. In this paper, we report an event where particle flux enhancements due to substorm injections are clearly identified in the MEPD A observations at energies of tens of keV. Additionally, we report a specific example observation of the electron distributions over a wide energy range in which we identify electron spatial distributions with energies of tens to hundreds of keV from the MEPD and with energy ranging up to a few MeV from the HEPD in the slot region and outer radiation belts. In addition, for an ~1.5-year period, we confirm that the HEPD successfully observed the well-known outer radiation belt electron flux distributions and their variations in time and L shell in a way consistent with the geomagnetic disturbance levels. Last, we find that the inner edge of the outer radiation belt is mostly coincident with the plasmapause locations in L, somewhat more consistent at subrelativistic energies than at relativistic energies. Based on these example events, we conclude that the SRD observations are of reliable quality, so they are useful for understanding the dynamics of the inner magnetosphere, including substorms and radiation belt variations.

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“…We can use data from neutron monitors recently installed in Jang Bogo station (Jung et al 2016) on the ground to study the space environment. We have access to data from the High Energy Particle Detector (HEPD) (Sohn et al 2012;Jo et al 2014;Sohn et al 2018) of Instruments for the study of Stable/Storm-time Space (ISSS) (Choi et al 2014) onboard the Next Generation Small Satellite-1 (NEXTSat-1) (Shin et al 2014a, b), which will be launched this year, to understand the plasma structures in the near-Earth space environment.…”

Section: Introductionmentioning

confidence: 99%

Conceptual Design of a Solid State Telescope for Small scale magNetospheric Ionospheric Plasma Experiments

Sohn¹,

Lee²,

Jo³

et al. 2018

Journal of Astronomy and Space Sciences

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The present paper describes the design of a Solid State Telescope (SST) on board the Korea Astronomy and Space Science Institute satellite-1 (KASISat-1) consisting of four [TBD] nanosatellites. The SST will measure these radiation belt electrons from a low-Earth polar orbit satellite to study mechanisms related to the spatial resolution of electron precipitation, such as electron microbursts, and those related to the measurement of energy dispersion with a high temporal resolution in the sub-auroral regions. We performed a simulation to determine the sensor design of the SST using GEometry ANd Tracking 4 (GEANT4) simulations and the Bethe formula. The simulation was performed in the range of 100 ~ 400 keV considering that the electron, which is to be detected in the space environment. The SST is based on a silicon barrier detector and consists of two telescopes mounted on a satellite to observe the electrons moving along the geomagnetic field (pitch angle 0°) and the quasi-trapped electrons (pitch angle 90°) during observations. We determined the telescope design of the SST in view of previous measurements and the geometrical factor in the cylindrical geometry of Sullivan (1971). With a high spectral resolution of 16 channels over the 100 keV ~ 400 keV energy range, together with the pitch angle information, the designed SST will answer questions regarding the occurrence of microbursts and the interaction with energetic particles. The KASISat-1 is expected to be launched in the latter half of 2020.

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HEPD on NEXTSat-1: A High Energy Particle Detector for Measurements of Precipitating Radiation Belt Electrons

Cited by 6 publications

References 33 publications

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

Multi‐Year Statistics of LEO Energetic Electrons as Observed by the Korean NextSat‐1

A Substorm Injection Event and the Radiation Belt Structure Observed by Space Radiation Detectors onboard Next Generation Small Satellite-1 (NEXTSat-1)

Conceptual Design of a Solid State Telescope for Small scale magNetospheric Ionospheric Plasma Experiments

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