Search Publications
Revisiting mirror modes in the plasma environment of comet 67P/Churyumov-Gerasimenko
Goetz, Charlotte; Volwerk, Martin; Tello Fallau, Ariel +2 more
The plasma environment of comet 67P provides a unique laboratory to study plasma phenomena in the interplanetary medium. There, waves are generated which help the plasma relax back to stability through wave-particle interactions, transferring energy from the wave to the particles and vice versa. In this study, we focus on mirror-mode-like structur…
Warm protons at comet 67P/Churyumov-Gerasimenko - implications for the infant bow shock
Nilsson, Hans; Goetz, Charlotte; Gunell, Herbert +4 more
The plasma around comet 67P/Churyumov-Gerasimenko showed remarkable variability throughout the entire Rosetta mission. Plasma boundaries such as the diamagnetic cavity, solar wind ion cavity and infant bow shock separate regions with distinct plasma parameters from each other. Here, we focus on a particular feature in the plasma: warm, slow solar …
Steepening of magnetosonic waves in the inner coma of comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Goetz, Charlotte; Richter, Ingo +7 more
We present a statistical survey of large-amplitude, asymmetric plasma and magnetic field enhancements detected outside the diamagnetic cavity at comet 67P/Churyumov-Gerasimenko from December 2014 to June 2016. Based on the concurrent observations of plasma and magnetic field enhancements, we interpret them to be magnetosonic waves. The aim is to p…
Ion acoustic waves near a comet nucleus: Rosetta observations at comet 67P/Churyumov-Gerasimenko
Henri, Pierre; Nilsson, Hans; Goetz, Charlotte +6 more
Ion acoustic waves were observed between 15 and 30 km from the centre of comet 67P/Churyumov-Gerasimenko by the Rosetta spacecraft during its close flyby on 28 March 2015. There are two electron populations: one cold at kBTe≈0.2 eV and one warm at kBTe≈2 eV. The ions are dominated by a cold (a few hundre…
Multi-point galactic cosmic ray measurements between 1 and 4.5 AU over a full solar cycle
Guo, Jingnan; Heber, Bernd; Kuulkers, Erik +6 more
The radiation data collected by the Standard Radiation Environment Monitor (SREM) aboard ESA missions INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory), Rosetta, Herschel, Planck and Proba-1, and by the high-energy neutron detector (HEND) instrument aboard Mars Odyssey, are analysed with an emphasis on characterising galactic cosmic rays …
Mass-loading, pile-up, and mirror-mode waves at comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Glassmeier, K. -H.; Nilsson, H. +23 more
The data from all Rosetta plasma consortium instruments and from the ROSINA COPS instrument are used to study the interaction of the solar wind with the outgassing cometary nucleus of 67P/Churyumov-Gerasimenko. During 6 and 7 June 2015, the interaction was first dominated by an increase in the solar wind dynamic pressure, caused by a higher solar …
Two-point observations of low-frequency waves at 67P/Churyumov-Gerasimenko during the descent of PHILAE: comparison of RPCMAG and ROMAP
Goetz, Charlotte; Tsurutani, Bruce T.; Richter, Ingo +11 more
The European Space Agency's spacecraft ROSETTA has reached its final destination, comet 67P/Churyumov-Gerasimenko. Whilst orbiting in the close vicinity of the nucleus the ROSETTA magnetometers detected a new type of low-frequency wave possibly generated by a cross-field current instability due to freshly ionized cometary water group particles. Du…
Modified ion-Weibel instability as a possible source of wave activity at Comet 67P/Churyumov-Gerasimenko
Motschmann, Uwe; Glassmeier, Karl-Heinz; Meier, Patrick
We analytically discuss wave excitation in a homogeneous three component plasma consisting of solar wind protons, electrons and a beam of cometary water ions applied to the plasma environment of comet 67P/Churyumov-Gerasimenko. The resulting dispersion relations are studied in a solar wind rest frame, where a cometary current is solely generated b…
Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Tsurutani, B. T.; Glassmeier, K. -H. +23 more
We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions wh…
A comparison between VEGA 1, 2 and Giotto flybys of comet 1P/Halley: implications for Rosetta
Glassmeier, K. -H.; Volwerk, M.; Richter, I. +4 more
Three flybys of comet 1P/Halley, by VEGA 1, 2 and Giotto, are investigated with respect to the occurrence of mirror mode waves in the cometosheath and field line draping in the magnetic pile-up region around the nucleus. The time interval covered by these flybys is approximately 8 days, which is also the approximate length of an orbit or flyby of …