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Authors: Yoon Peter H., Hwang Junga, Kim Hyangpyo, and Seough Jungjoon
Title: Quasi Thermal Noise Spectroscopy for Van Allen Probes
Abstract:

Quasi thermal fluctuations in the Langmuir/upper-hybrid frequency range are pervasively observed in space plasmas including the radiation belt and the ring current region of inner magnetosphere as well as the solar wind. The quasi thermal noise spectroscopy may be employed in order to determine the electron density and temperature as well as to diagnose the properties of energetic electrons when direct measurements are not available. However, when employing the technique, one must carefully take the spacecraft orientation into account. The present paper takes the upper-hybrid and multiple harmonic—or (n + 1/2)fce—emissions measured by the Van Allen Probes as an example in order to illustrate how the spacecraft antenna geometrical factor can be incorporated into the theore. . .
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026460 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA026460
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Authors: Yoon Peter H., Hwang Junga, Kim Hyangpyo, and Seough Jungjoon
Title: Quasi Thermal Noise Spectroscopy for Van Allen Probes
Abstract:

Quasi thermal fluctuations in the Langmuir/upper-hybrid frequency range are pervasively observed in space plasmas including the radiation belt and the ring current region of inner magnetosphere as well as the solar wind. The quasi thermal noise spectroscopy may be employed in order to determine the electron density and temperature as well as to diagnose the properties of energetic electrons when direct measurements are not available. However, when employing the technique, one must carefully take the spacecraft orientation into account. The present paper takes the upper-hybrid and multiple harmonic—or (n + 1/2)fce—emissions measured by the Van Allen Probes as an example in order to illustrate how the spacecraft antenna geometrical factor can be incorporated into the theore. . .
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026460 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA026460
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Authors: Yoon P. H., Seough J., Salem C. S., and Klein K. G.
Title: Solar Wind Temperature Isotropy
Abstract:

Reliable models of the solar wind in the near-Earth space environment may constrain conditions close to the Sun. This is relevant to NASA's contemporary innerheliospheric mission Parker Solar Probe. Among the outstanding issues is how to explain the solar wind temperature isotropy. Perpendicular and parallel proton and electron temperatures near 1 AU are theoretically predicted to be unequal, but in situ observations show quasi-isotropy sufficiently below the instability threshold condition. This has not been satisfactorily explained. The present Letter shows that the dynamical coupling of electrons and protons via collisional processes and instabilities may contribute toward the resolution of this problem.


Date: 10/2019 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.123.145101 Available at: https://link.aps.org/doi/10.1103/PhysRevLett.123.145101http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.123.145101/fulltexthttps://link.aps.org/article/10.1103/PhysRevLett.123.145101
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Authors: Yoon Peter H., Hwang Junga, ópez Rodrigo A., Kim Sunjung, and Lee Jaejin
Title: Electromagnetic Thermal Noise in Upper-Hybrid Frequency Range
Abstract:

The inner magnetosphere including the radiation belt and ring current environment is replete with high-frequency fluctuations with peak intensity occurring near upper-hybrid frequency and/or multiple harmonic electron cyclotron frequencies above and below the upper-hybrid frequency. Past and contemporary spacecraft missions, including the Van Allen Probes, were designed to detect the electric field spectrum only for these high-frequency fluctuations. Making use of the recently formulated generalized theory of electromagnetic spontaneous emission in thermal magnetized plasmas, it is shown that upper-hybrid/multiple harmonic electron cyclotron emissions are characterized by a significant magnetic field component, even in the high-frequency regime. Such a prediction may potentially be test. . .
Date: 07/2018 Publisher: Journal of Geophysical Research: Space Physics Pages: 5356 - 5363 DOI: 10.1029/2018JA025459 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1029/2018JA025459/fullpdf
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Authors: Yoon Peter H., Hwang Junga, ópez Rodrigo A., Kim Sunjung, and Lee Jaejin
Title: Electromagnetic Thermal Noise in Upper-Hybrid Frequency Range
Abstract:

The inner magnetosphere including the radiation belt and ring current environment is replete with high-frequency fluctuations with peak intensity occurring near upper-hybrid frequency and/or multiple harmonic electron cyclotron frequencies above and below the upper-hybrid frequency. Past and contemporary spacecraft missions, including the Van Allen Probes, were designed to detect the electric field spectrum only for these high-frequency fluctuations. Making use of the recently formulated generalized theory of electromagnetic spontaneous emission in thermal magnetized plasmas, it is shown that upper-hybrid/multiple harmonic electron cyclotron emissions are characterized by a significant magnetic field component, even in the high-frequency regime. Such a prediction may potentially be test. . .
Date: 07/2018 Publisher: Journal of Geophysical Research: Space Physics Pages: 5356 - 5363 DOI: 10.1029/2018JA025459 Available at: http://onlinelibrary.wiley.com/wol1/doi/10.1029/2018JA025459/fullpdf
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Authors: Yoon P. H., Seough J., Salem C. S., and Klein K. G.
Title: Solar Wind Temperature Isotropy
Abstract:

Reliable models of the solar wind in the near-Earth space environment may constrain conditions close to the Sun. This is relevant to NASA’s contemporary innerheliospheric mission Parker Solar Probe. Among the outstanding issues is how to explain the solar wind temperature isotropy. Perpendicular and parallel proton and electron temperatures near 1 AU are theoretically predicted to be unequal, but in situ observations show quasi-isotropy sufficiently below the instability threshold condition. This has not been satisfactorily explained. The present Letter shows that the dynamical coupling of electrons and protons via collisional processes and instabilities may contribute toward the resolution of this problem.


Date: 10/2019 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.123.145101 Available at: https://link.aps.org/doi/10.1103/PhysRevLett.123.145101http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.123.145101/fulltexthttps://link.aps.org/article/10.1103/PhysRevLett.123.145101
More Details