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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

Van Allen Probes A and B EFW positive spacecraft potential in selected 1 V charging windows binned by 0.5 MLT and 0.25 L from February 2013 to April 2015 in the same format as Figure 2.
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swe20312-fig-0004: Van Allen Probes A and B EFW positive spacecraft potential in selected 1 V charging windows binned by 0.5 MLT and 0.25 L from February 2013 to April 2015 in the same format as Figure 2.

Mentions: We examine the 0–10 V charging window more closely by further dividing this window into 1 V bins; Figure 4 shows selected bins. Most observations at L < 4 show 0–1 V charging. By 2–3 V positive potential, there are almost no events at L < 3. Instead, there is a stronger likelihood of these positive events to occur in the dusk sector after MLT = 18 between 4 < L < 6. In the 4–5 V window, charging is most likely to occur at dawn with MLT = 6 just inside of L = 5. There are only a few events in the 8–9 V window, and they most often occur in the premidnight sector at L > 5. Positive charging appears to be related to the average plasmapause boundary at L = 4. Minimal positive spacecraft charging of 0 to 1 V occurs almost 100% of the time within L = 4. More intense positive charging events with charging >2 V occur outside of L = 4.


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)

Van Allen Probes A and B EFW positive spacecraft potential in selected 1 V charging windows binned by 0.5 MLT and 0.25 L from February 2013 to April 2015 in the same format as Figure 2.
© Copyright Policy - creativeCommonsBy-nc-nd
Related In: Results  -  Collection

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

swe20312-fig-0004: Van Allen Probes A and B EFW positive spacecraft potential in selected 1 V charging windows binned by 0.5 MLT and 0.25 L from February 2013 to April 2015 in the same format as Figure 2.
Mentions: We examine the 0–10 V charging window more closely by further dividing this window into 1 V bins; Figure 4 shows selected bins. Most observations at L < 4 show 0–1 V charging. By 2–3 V positive potential, there are almost no events at L < 3. Instead, there is a stronger likelihood of these positive events to occur in the dusk sector after MLT = 18 between 4 < L < 6. In the 4–5 V window, charging is most likely to occur at dawn with MLT = 6 just inside of L = 5. There are only a few events in the 8–9 V window, and they most often occur in the premidnight sector at L > 5. Positive charging appears to be related to the average plasmapause boundary at L = 4. Minimal positive spacecraft charging of 0 to 1 V occurs almost 100% of the time within L = 4. More intense positive charging events with charging >2 V occur outside of L = 4.

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