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Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes.

Sarno-Smith LK, Larsen BA, Skoug RM, Liemohn MW, Breneman A, Wygant JR, Thomsen MF - Space Weather (2016)

Bottom Line: We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT.An algorithm to extract the H(+) charging line in the HOPE instrument data was developed to better explore intense charging events.Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV.

View Article: PubMed Central - PubMed

Affiliation: Department of Climate and Space Engineering University of Michigan Ann Arbor Michigan USA.

ABSTRACT

Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H(+) charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV. It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. We also show noneclipse significant negative charging events on the Van Allen Probes.

No MeSH data available.


Related in: MedlinePlus

The negative spacecraft potential measured by EFW (orange) and HOPE (red) as a function of the electron energy flux (keV cm−2 s−1 sr−1 keV−1) measured by the HOPE instrument. All times of negative charging from both Van Allen Probes from February 2013 to April 2015 are included. (top column) The occurrence histograms of electron energy flux measurements throughout the mission (blue) and negative charging times (yellow).
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swe20312-fig-0007: The negative spacecraft potential measured by EFW (orange) and HOPE (red) as a function of the electron energy flux (keV cm−2 s−1 sr−1 keV−1) measured by the HOPE instrument. All times of negative charging from both Van Allen Probes from February 2013 to April 2015 are included. (top column) The occurrence histograms of electron energy flux measurements throughout the mission (blue) and negative charging times (yellow).

Mentions: Figure 7 shows the magnitude of negative charging measured by EFW and extracted HOPE instrument ion spectra compared to the HOPE energy fluxes at 30 eV, 50 eV, 300 eV, 500 eV, 3 keV, 5 keV, 30 keV, and 50 keV energies. The orange points are the EFW spacecraft potential measurements, which saturate at 200 V. The red points are the HOPE instrument ion charging line extracted results above 10 V of negative surface charging over the same time period. Charging derived using the HOPE spectra reaches 1000 V at times.


Spacecraft surface charging within geosynchronous orbit observed by the Van Allen Probes.

Sarno-Smith LK, Larsen BA, Skoug RM, Liemohn MW, Breneman A, Wygant JR, Thomsen MF - Space Weather (2016)

The negative spacecraft potential measured by EFW (orange) and HOPE (red) as a function of the electron energy flux (keV cm−2 s−1 sr−1 keV−1) measured by the HOPE instrument. All times of negative charging from both Van Allen Probes from February 2013 to April 2015 are included. (top column) The occurrence histograms of electron energy flux measurements throughout the mission (blue) and negative charging times (yellow).
© Copyright Policy - creativeCommonsBy-nc-nd
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4933096&req=5

swe20312-fig-0007: The negative spacecraft potential measured by EFW (orange) and HOPE (red) as a function of the electron energy flux (keV cm−2 s−1 sr−1 keV−1) measured by the HOPE instrument. All times of negative charging from both Van Allen Probes from February 2013 to April 2015 are included. (top column) The occurrence histograms of electron energy flux measurements throughout the mission (blue) and negative charging times (yellow).
Mentions: Figure 7 shows the magnitude of negative charging measured by EFW and extracted HOPE instrument ion spectra compared to the HOPE energy fluxes at 30 eV, 50 eV, 300 eV, 500 eV, 3 keV, 5 keV, 30 keV, and 50 keV energies. The orange points are the EFW spacecraft potential measurements, which saturate at 200 V. The red points are the HOPE instrument ion charging line extracted results above 10 V of negative surface charging over the same time period. Charging derived using the HOPE spectra reaches 1000 V at times.

Bottom Line: We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT.An algorithm to extract the H(+) charging line in the HOPE instrument data was developed to better explore intense charging events.Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV.

View Article: PubMed Central - PubMed

Affiliation: Department of Climate and Space Engineering University of Michigan Ann Arbor Michigan USA.

ABSTRACT

Using the Helium Oxygen Proton Electron (HOPE) and Electric Field and Waves (EFW) instruments from the Van Allen Probes, we explored the relationship between electron energy fluxes in the eV and keV ranges and spacecraft surface charging. We present statistical results on spacecraft charging within geosynchronous orbit by L and MLT. An algorithm to extract the H(+) charging line in the HOPE instrument data was developed to better explore intense charging events. Also, this study explored how spacecraft potential relates to electron number density, electron pressure, electron temperature, thermal electron current, and low-energy ion density between 1 and 210 eV. It is demonstrated that it is imperative to use both EFW potential measurements and the HOPE instrument ion charging line for examining times of extreme spacecraft charging of the Van Allen Probes. The results of this study show that elevated electron energy fluxes and high-electron pressures are present during times of spacecraft charging but these same conditions may also occur during noncharging times. We also show noneclipse significant negative charging events on the Van Allen Probes.

No MeSH data available.


Related in: MedlinePlus