Dynamic unmagnetized plasma in the diamagnetic cavity around comet 67P/Churyumov-Gerasimenko

Wattieaux, Gaetan (författare): Univ Toulouse, LAPLACE, CNRS, F-31062 Toulouse, France

Goetz, Charlotte (författare): TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany

Richter, Ingo (författare): TU Braunschweig, Inst Geophys & Extraterr Phys, Mendelssohnstr 3, D-38106 Braunschweig, Germany

Tsurutani, Bruce T. (författare): CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA

Gunell, Herbert (författare): Umeå universitet,Institutionen för fysik,Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Avenue Circulaire 3, B-1180 Brussels, Belgium,Royal Belgian Inst Space Aeron BIRA IASB, Ave Circulaire 3, B-1180 Brussels, Belgium;Umea Univ, Dept Phys, SE-90187 Umea, Sweden

Nilsson, Hans (författare): Swedish Inst Space Phys, POB 812, SE-98128 Kiruna, Sweden

Eriksson, Anders (författare): Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen

Nemeth, Zoltan (författare): Wigner Res Ctr Phys, Konkoly Thege M Rd 29-33, Budapest, Hungary

Burchdegrees, James L. (författare): Southwest Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA

Rubin, Martin (författare): Univ Bern, Inst Phys, Sidlerstr 5, CH-3012 Bern, Switzerland

(creator_code:org_t)

2018-01-12
2018
Engelska.
Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 475:3, s. 4140-4147

Relaterad länk:: https://boris.unibe....; visa fler...; https://urn.kb.se/re...; https://doi.org/10.1...; https://urn.kb.se/re...; visa färre...

Abstract Ämnesord

Stäng

The Rosetta orbiter witnessed several hundred diamagnetic cavity crossings (unmagnetized regions) around comet 67P/Churyumov-Gerasimenko during its two year survey of the comet. The characteristics of the plasma environment inside these diamagnetic regions are studied using in situ measurements by the Rosetta Plasma Consortium instruments. Although the unmagnetized plasma density has been observed to exhibit little dynamics compared to the very dynamical magnetized cometary plasma, we detected several localized dynamic plasma structures inside those diamagnetic regions. These plasma structures are not related to the direct ionization of local cometary neutrals. The structures are found to be steepened, asymmetric plasma enhancements with typical rising-to-descending slope ratio of similar to 2.8 (+/- 1.9), skewness similar to 0.43 (+/- 0.36), mean duration of similar to 2.7 (+/- 0.9) min and relative density variation Delta N/N of similar to 0.5 (+/- 0.2), observed close to the electron exobase. Similar steepened plasma density enhancements were detected at the magnetized boundaries of the diamagnetic cavity as well as outside the diamagnetic region. The plausible scalelength and propagation direction of the structures are estimated from simple plasma dynamics considerations. It is suggested that they are large-scale unmagnetized plasma enhancements, transmitted from the very dynamical outer magnetized region to the inner magnetic field-free cavity region.

Av författaren/redakt...: Hajra, Rajkumar; Henri, Pierre; Vallières, Xavie ...; More, Jeromé; Gilet, Nicolas; Wattieaux, Gaeta ...; visa fler...; Goetz, Charlotte; Richter, Ingo; Tsurutani, Bruce ...; Gunell, Herbert; Nilsson, Hans; Eriksson, Anders; Nemeth, Zoltan; Burchdegrees, Ja ...; Rubin, Martin; visa färre...

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