The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

Goetz, Charlotte; Béhar, Etienne; Beth, Arnaud; Bodewits, Dennis; Bromley, Steven M.; Burch, J. L.; Deca, Jan; Divin, Andrey; Eriksson, Anders; Feldman, P. D.; Galand, M.; Gunell, H.; Henri, Pierre; Héritier, K. L.; Jones, G. H.; Mandt, K.; Nilsson, Hans; Noonan, John; Odelstad, Elias; Parker, J. W.; Rubin, Martin; Wedlund, Cyril Simon; Stephenson, Peter; Taylor, M. G. G. T.; Vigren, Erik; Vines, S. K.; Volwerk, M.

doi:10.1007/s11214-022-00931-1

Cited by 19 publications

(22 citation statements)

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“…Once the plasma environment is of a similar spatial scale as the ion gyroradius, kinetic effects have to be taken into account. This is the case for comet 67P, especially at a low outgassing rate far away from the Sun (Goetz et al., 2022).…”

Section: Introductionmentioning

confidence: 94%

Indirect Observations of Electric Fields at Comet 67P

Moeslinger,

Nilsson,

Stenberg Wieser

et al. 2023

JGR Space Physics

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No spacecraft visiting a comet has been equipped with instruments to directly measure the static electric field. However, the electric field can occasionally be estimated indirectly by observing its effects on the ion velocity distribution. We present such observations made by the Rosetta spacecraft on 19 April 2016, 35 km from the nucleus. At this time comet 67P was at a low outgassing rate and the plasma environment was relatively stable. The ion velocity distributions show the cometary ions on the first half of their gyration. We estimate the bulk drift velocity and the gyration speed from the distributions. By using the local measured magnetic field and assuming an E × B drift of the gyrocentre, we get an estimate for the average electric field driving this ion motion. We analyze a period of 13 hr, during which the plasma environment does not change drastically. We find that the average strength of the perpendicular electric field component is 0.21 mV/m. The direction of the electric field is mostly anti‐sunward. This is in agreement with previous results based on different methods.

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Section: Introductionmentioning

confidence: 94%

Indirect Observations of Electric Fields at Comet 67P

Moeslinger,

Nilsson,

Stenberg Wieser

et al. 2023

JGR Space Physics

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“…It accompanied comet 67P for 2 years and observed large variations in its cometary activity as the heliocentric distance changed from about 3.6 AU to 1.24 AU. This provided us with unique measurements of the evolving plasma environment (Glassmeier, Boehnhardt, et al., 2007; Goetz et al., 2022; Taylor et al., 2017). In the beginning of the mission, the low cometary activity presented no significant obstacle to the solar wind, which was observed from the anti‐sunward direction with little to no deflection (Behar et al., 2016).…”

Section: Introductionmentioning

confidence: 99%

Solar Wind Protons Forming Partial Ring Distributions at Comet 67P

et al. 2023

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Comets are a highly diverse group of solar system bodies that are mainly comprised of ice and organic material (Filacchione et al., 2019). They are known for their vast tails resulting from the ices on their surface sublimating when the comets approach the sun. Cometary activity can be defined by the amount of volatiles that a comet releases into space. An example of a high-activity comet is 1P/Halley, which has been the target of several space missions, for example, ESA's Giotto mission (Reinhard, 1987). The atmosphere of such high-activity comets, especially at perihelion, can extend millions of kilometres from the nucleus. Low-activity comets (Hansen et al., 2016), such as 67P/Churyumov-Gerasimenko (hereafter 67P), only have a tenuous atmosphere that might span no more than a few thousand kilometres. The cometary activity is driven by the strength of the solar radiation and strongly varies over time due to the comet's highly elliptical orbit. The significant change in activity also changes the plasma environment around the comet with different plasma boundaries forming at certain heliocentric distances (Mandt et al., 2016).The Rosetta mission has so far been the only mission to orbit a comet. It accompanied comet 67P for 2 years and observed large variations in its cometary activity as the heliocentric distance changed from about 3.6 AU to 1.24

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“…The diamagnetic cavity has been observed at both comet Halley (e.g., Neubauer et al 1986) and comet 67P (e.g., Goetz et al 2016). Illustrations of the cometary magnetosphere can be found in, for example, Goetz et al (2022).…”

Section: Introductionmentioning

confidence: 99%

Spacecraft Charging Simulations of Probe B1 of Comet Interceptor during the Cometary Flyby

Bergman,

Miyake,

Kasahara

et al. 2023

ApJ

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Comet Interceptor will be the first mission to make a flyby of a long-period or interstellar comet. After launch, the spacecraft will wait at the Sun–Earth Lagrange point L2 for a yet-to-be-discovered comet to appear. The mission comprises three spacecraft: One main spacecraft, A, developed by ESA, and two subprobes, B1 and B2, developed by JAXA and ESA, respectively. All spacecraft will carry plasma instruments for a three-dimensional sampling of the cometary plasma environment. The plasma measurements will likely be affected by the spacecraft potential and by particles emitted from the spacecraft surface. In this work, we use the Spacecraft Plasma Interaction Software and the ElectroMagnetic Spacecraft Environment Simulator to make particle-in-cell simulations of the spacecraft–plasma interactions of probe B1 in different environments during the cometary flyby. This is done for two production rates of the target comet and two relative flyby velocities of the probe. At low flyby velocities, the spacecraft potential varies from 9 V in the solar wind to −5 V in the inner coma for a comet similar to comet 67P/Churyumov–Gerasimenko. For a comet similar to 1P/Halley, the potential is slightly less negative in the inner coma due to the more effective collisional cooling of the electrons in the environment. At high flyby velocities, secondary electron emissions from neutral gas impacts dominate the currents, charging the probe to positive potentials in most of the studied environments.

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The Plasma Environment of Comet 67P/Churyumov-Gerasimenko

Cited by 19 publications

References 402 publications

Indirect Observations of Electric Fields at Comet 67P

Indirect Observations of Electric Fields at Comet 67P

Solar Wind Protons Forming Partial Ring Distributions at Comet 67P

Spacecraft Charging Simulations of Probe B1 of Comet Interceptor during the Cometary Flyby

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