Comets: Rosetta results and related science
Increasing activity from comet 67P/Churyumov-Gerasimenko measured with the Rosetta Plasma Consortium
Andrew Coates
Jim Burch, Ray Goldstein, Tom Broiles (SwRI), Hans Nilsson, Gabriella Stenberg Wieser, Etienne Behar, Anders Eriksson (IRF), Chris Carr (Imperial College London), Karl-Heinz Glassmeier, Christoph Koenders (TUB), Jean-Pierre Lebreton, Pierre Henri (LPCE),
Since Rosetta’s arrival at comet 67P in August 2014, the Rosetta Plasma Consortium has provided exciting new data on the comet-solar wind interaction from its five sensors. The particle instruments (Ion Composition Analyser, ICA, and Ion and Electron Spectrometer, IES) have shown that the low activity cometary environment is increasingly dominated by cometary plasma and its interaction with the solar wind (Nilsson et al., Science 2015, Goldstein et al., GRL submitted 2015). This was expected in the early stages of the mission (e.g., Trotignon et al., 1999, Coates 2012). In addition to the solar wind and related He+ and H- populations, a low energy pickup ion population is seen intermittently (Nilsson et al., Science 2015, Goldstein et al., GRL submitted 2015). The population is very time dependent, but at times reaches higher energy, approaching the solar wind energy. During these intervals, ICA composition data indicate that the ions constitute a ‘spring’ of water group ions (Nilsson et al., 2015). The rising energy signatures of these ions observed at times indicate that they are in the early phases of the pickup process (see Nilsson et al, 2015). In addition to the particle data, the magnetometer MAG has shown evidence for wave activity produced by the comet-solar wind interaction which has been called the ‘singing comet’ (Richter et al. 2015) The Langmuir probe, LAP, and Mutual Impedance Probe (MIP) have also seen signs of cometary activity. Here, we summarise these and other results and look forward to what may be expected as the comet approaches perihelion in August 2015.
09:00 - 10:30