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Dynamics of solar wind protons reflected by the Moon
Barabash, S.; Holmström, M.; Futaana, Y. +2 more
Solar system bodies that lack a significant atmosphere and significant internal magnetic fields, such as the Moon and asteroids, have been considered passive absorbers of the solar wind. However, ion observations near the Moon by the SELENE spacecraft show that a fraction of the impacting solar wind protons are reflected by the surface of the Moon…
Evolution of low-altitude and ring current ENA emissions from a moderate magnetospheric storm: Continuous and simultaneous TWINS observations
Roelof, E.; McComas, D. J.; Brandt, P. C. +6 more
The moderate storm of 22 July 2009 is the largest measured during the extended solar minimum between December 2006 and March 2010. We present observations of this storm made by the two wide-angle imaging neutral-atom spectrometers (TWINS) mission. The TWINS mission measures energetic neutral atoms (ENAs) using sensors mounted on two separate space…
Protons in the near-lunar wake observed by the Sub-keV Atom Reflection Analyzer on board Chandrayaan-1
Barabash, S.; Holmström, M.; Futaana, Y. +7 more
Significant proton fluxes were detected in the near-wake region of the Moon by an ion mass spectrometer on board Chandrayaan-1. The energy of these nightside protons is slightly higher than the energy of the solar wind protons. The protons are detected close to the lunar equatorial plane at a 140° solar zenith angle, that is, ∼50° behind the termi…
Observations of X-ray and EUV fluxes during X-class solar flares and response of upper ionosphere
Mahajan, K. K.; Lodhi, Neelesh K.; Upadhayaya, Arun K.
Most studies dealing with solar flare effects in the upper ionosphere, where ionization is caused by EUV photons, have been based upon X-ray fluxes measured by the SOLRAD and GOES series of satellites. To check the validity of such studies, we compare simultaneous observations of GOES X-ray fluxes and SOHO EUV fluxes for 10 X-class solar flares wh…
Generation of whistler mode emissions in the inner magnetosphere: An event study
Pickett, J. S.; Winningham, D.; Fazakerley, A. N. +8 more
On July 24, 2003, when the Cluster 4 satellite crossed the magnetic equator at about 4.5 RE radial distance on the dusk side (∼15 MLT), whistler wave emissions were observed below the local electron gyrofrequency (fce) in two bands, one band above one-half the gyrofrequency (0.5fce) and the other band below 0.5f
In situ observations of the effect of a solar wind compression on Saturn's magnetotail
Coates, A. J.; Dougherty, M. K.; Jackman, C. M. +4 more
In this paper we explore the dynamic response of Saturn's magnetotail to an episode of solar wind compression that took place while Cassini was sampling Saturn's nightside equatorial magnetosphere in 2006. Following an initial increase in solar wind dynamic pressure the magnetosphere was compressed, but over several subsequent days the flaring of …
Ion transport in Titan's upper atmosphere
Dougherty, M. K.; Wahlund, J. -E.; Ågren, K. +4 more
Based on a combined Cassini data set including Ion Neutral Mass Spectrometer, Radio Plasma Wave Science, and Magnetometer measurements made during nine close encounters of the Cassini spacecraft with Titan, we investigate the electron (or total ion) distribution in the upper ionosphere of the satellite between 1250 and 1600 km. A comparison of the…
Time development of field-aligned currents, potential drops, and plasma associated with an auroral poleward boundary intensification
Goldstein, M. L.; McFadden, J. P.; Mozer, F. S. +5 more
We present a detailed case study of the plasma and fields measured by the Cluster spacecraft fleet at the high-altitude auroral zone (∼3.5 RE) across the plasma sheet boundary layer and into the polar cap. This event, which occurred during quiet geomagnetic conditions (Kp = 1+, AE = 50 nT), is of particular interest in that C…
Magnetospheric period oscillations of Saturn's bow shock
Coates, A. J.; Masters, A.; Andrews, D. J. +2 more
Using magnetic field and plasma electron data from 35 Cassini orbits on which the spacecraft crossed Saturn's magnetopause and bow shock during 2004-2007, we provide first evidence for bow shock oscillations related to oscillations in the magnetic field and plasma inside the magnetosphere near the ∼11 h planetary rotation period, termed here the “…
Ionization sources in Titan's deep ionosphere
Galand, Marina; Yelle, Roger; Coates, Andrew +4 more
We analyze a multi-instrumental data set from four Titan encounters by the Cassini spacecraft to investigate in detail the formation of the ionosphere. The data set includes observations of thermospheric and ionospheric species and suprathermal electrons. A model describing the solar and electron energy deposition is used as an organizing element …