Search Publications
Low-frequency electromagnetic plasma waves at comet P/Grigg-Skjellerup: Overview and spectral characteristics
Neubauer, Fritz M.; Glassmeier, Karl-Heinz
Large-amplitude electromagnetic plasma waves are one of the dominant features of the solar wind-comet interaction. Wave characteristics strongly depend on parameters such as the solar wind flow and Alfvén velocities and the angle between flow and interplanetary magnetic field as well as the production rate. With respect to the latter the flyby of …
Mirror modes and fast magnetoacoustic waves near the magnetic pileup boundary of comet P/Halley
Motschmann, Uwe; Neubauer, Fritz M.; Fuselier, S. A. +4 more
Large-amplitude ultralow-frequency wave structures observed on both sides of the magnetic pileup boundary of comet P/Halley during the flyby of the Giotto spacecraft have been analyzed using suprathermal electron density and magnetic field observations. Upstream of the boundary, electron density and magnetic field magnitude variations are anticorr…
Velocity space diffusion and nongyrotropy of pickup water group ions at comet Grigg-Skjellerup
Coates, A. J.; Neubauer, Fritz M.; Wilken, B. +1 more
The diffusion of water group cometary ions in velocity space at comet Grigg-Skjellerup was measured during the Giotto spacecraft encounter. The evolution of the collapsed pitch angle and energy distributions during the inbound and outbound passes shows that the timescale for energy diffusion may be similar to that for pitch angle diffusion. Fully …
Low-frequency electromagnetic plasma waves at comet P/Grigg-Skjellerup analysis and interpretation
Coates, A. J.; Neubauer, Fritz M.; Glassmeier, Karl-Heinz +1 more
The propagation and polarization characteristics of low-frequency electromagnetic wave fields near comet P/Grigg-Skjellerup (P/GS) are analyzed using magnetic field and plasma observations obtained by the Giotto magnetometer experiment and the Johnstone plasma analyzer during the encounter at the comet on July 10, 1992. The results have been physi…
Mass loading and velocity diffusion models for heavy pickup ions at comet Grigg-Skjellerup
Coates, A. J.; Neubauer, Fritz M.; Johnstone, A. D. +1 more
We compare model predictions of cometary water group ion densities and the solar wind slow down with measurements made by the Giotto Johnstone plasma analyzer implanted ion sensor at the encounter with comet Grigg-Skjellerup (G-S) on July 10, 1992. The observed slope of the ion density profile on approach to the comet is unexpectedly steep. Possib…
MHD modeling applied to Giotto encounter with comet P/Grigg-Skjellerup
Neubauer, Fritz M.; Wegmann, R.; Schmidt, H. U.
First from a one-dimensional MHD model we derive estimates for position and shape of the bow shock applicable for arbitrary magnetosonic Mach numbers >1 in the solar wind. This generalization is important in the case of the Giotto encounter with P/Grigg-Skjellerup with the unusual interplanetary magnetic field (IMF) of 18 nT. We compare three-d…
Giotto's second encounter: The mission to comet P/Grigg-Skjellerup
Schwehm, G.; Grensemann, M. G.
The second highlight in the life of the Giotto spacecraft, which was originally designed for a short 8-month lifetime, occurred on 10 July 1992. The main mission was to explore and photograph Halley's Comet; however, not only did Giotto survive the harsh environment around the comet Halley but is was also able, after more than 7 years in orbit aro…
On the momentum balance along the comet Halley-Sun line during the Giotto flyby
Neubauer, F. M.; Israelevich, P. L.; Ershkovich, A. I.
The plasma velocity along the Sun-comet Halley line is derived by using in situ measurements of the magnetic field along the Giotto trajectory. Including this velocity profile in the momentum balance turns out to be insufficient in order to support the magnetic barrier with conventional parameters of ion-neutral interaction. The observed magnetic …