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[PEM12-P21] Isolated Electrostatic Potentials Observed by the Arase Satellite
Keywords:Electrostatic Solitary Waves, Isolated Potentials, Interferometry observation, Arase satellite, Time domain structures
The present paper discuss the estimation of the spatial structure of the isolated electrostatic potentials observed by the Arase satellite in the Earth’s inner magnetosphere applying the interferometry technique.
Isolated electrostatic potentials in the Earth's magnetosphere have been observed as Electrostatic Solitary Waves (ESWs) by many satellites such as GEOTAIL, RBSP, Polar, and FAST. It has been suggested that the isolated potentials contribute to electron acceleration in the magnetosphere because they may lead to spatial steps in the potential. Therefore, the spatial scale and structure of the isolated potentials and their electric energy are important. In the magnetotail region, a sheet-like structure represented by one-dimensional Gaussian was proposed, based on the ESW features observed by the GEOTAIL satellite. On the other hand, no specific spatial structure has been proposed for the isolated potential observed in the Earth's inner magnetosphere.
The purpose of this study is to propose a spatial structure of the isolated potentials observed by the Arase satellite. For this purpose, we calculate the spatial scale and polarity of the ESW observed by the Arase satellite, and propose a spatial structure model of the isolated potential that can reproduce the ESWs.
Using the monopole observation of the Arase satellite, it is possible to determine the direction of passage of the isolated potential relative to the satellite and the time difference between the two observation points. This provides the spatial scale of the potential. It is also possible to determine the polarity of the isolated potentials by considering the direction of its passage and the antenna polarity. In addition, the structure of the isolated potentials is discussed. Assuming a two-dimensional model of the electrostatic potential, numerical experiments are conducted to reproduce the waveform observed by Arase.
The ESWs observed by the Arase satellite have two characteristics: pulse waveforms are observed not only parallel but also perpendicular to the background magnetic field, and various types of waveforms such as bipolar and asymmetric waveforms are irregularly observed. We analyzed the waveforms of the monopole observations, focusing on the bipolar waveforms. The spatial scales are estimated to be between 380m and 3 km. The potentials with both positive and negative polarities are present. A model with a small scale structure in the perpendicular direction to the background magnetic field was proposed, and the above features could be reproduced in two-dimensional Gaussian by numerical experiments.
By using the monopole observations of the Arase satellite, we have succeeded in calculating the spatial scale of the isolated potential and determining their polarity. It is suggested that the isolated potentials observed by the Arase satellite has a different structure from the previously proposed model.
It is also suggested that the proposed structure does not have potential step and does not contribute to the acceleration of electrons.
Isolated electrostatic potentials in the Earth's magnetosphere have been observed as Electrostatic Solitary Waves (ESWs) by many satellites such as GEOTAIL, RBSP, Polar, and FAST. It has been suggested that the isolated potentials contribute to electron acceleration in the magnetosphere because they may lead to spatial steps in the potential. Therefore, the spatial scale and structure of the isolated potentials and their electric energy are important. In the magnetotail region, a sheet-like structure represented by one-dimensional Gaussian was proposed, based on the ESW features observed by the GEOTAIL satellite. On the other hand, no specific spatial structure has been proposed for the isolated potential observed in the Earth's inner magnetosphere.
The purpose of this study is to propose a spatial structure of the isolated potentials observed by the Arase satellite. For this purpose, we calculate the spatial scale and polarity of the ESW observed by the Arase satellite, and propose a spatial structure model of the isolated potential that can reproduce the ESWs.
Using the monopole observation of the Arase satellite, it is possible to determine the direction of passage of the isolated potential relative to the satellite and the time difference between the two observation points. This provides the spatial scale of the potential. It is also possible to determine the polarity of the isolated potentials by considering the direction of its passage and the antenna polarity. In addition, the structure of the isolated potentials is discussed. Assuming a two-dimensional model of the electrostatic potential, numerical experiments are conducted to reproduce the waveform observed by Arase.
The ESWs observed by the Arase satellite have two characteristics: pulse waveforms are observed not only parallel but also perpendicular to the background magnetic field, and various types of waveforms such as bipolar and asymmetric waveforms are irregularly observed. We analyzed the waveforms of the monopole observations, focusing on the bipolar waveforms. The spatial scales are estimated to be between 380m and 3 km. The potentials with both positive and negative polarities are present. A model with a small scale structure in the perpendicular direction to the background magnetic field was proposed, and the above features could be reproduced in two-dimensional Gaussian by numerical experiments.
By using the monopole observations of the Arase satellite, we have succeeded in calculating the spatial scale of the isolated potential and determining their polarity. It is suggested that the isolated potentials observed by the Arase satellite has a different structure from the previously proposed model.
It is also suggested that the proposed structure does not have potential step and does not contribute to the acceleration of electrons.