Search Publications
Widely different characteristics of oxygen and hydrogen ion escape from Venus
Kallio, E.; Janhunen, P.; Jarvinen, R. +2 more
We study the solar wind induced escape of O+ and H+ ions from Venus' atmosphere in the HYB-Venus hybrid simulation. Most of the previous Venus global plasma modelling studies have concentrated only on the O+ escape. According to the hybrid simulation, planetary O+ and H+ ions behave very diffe…
Oxygen energization by localized perpendicular electric fields at the cusp boundary
Waara, M.; Nilsson, H.; André, M. +3 more
We report Cluster observations of oxygen energization by several keV at the boundary between the high latitude cusp and lobe. A localized electric field at the cusp/lobe boundary is responsible for a significant part of the observed energization. Such electric fields can be related to the separatrix region of reconnection at the magnetopause. Ions…
Global configuration of Saturn's magnetic field derived from observations
Dougherty, M. K.; Khurana, K. K.; Carbary, J. F. +2 more
Magnetic field observations from the Cassini spacecraft are averaged into 1 × 1 RS (1 RS = 60238 km) meridional bins at Saturn. A Runge-Kutta procedure uses the bin-averaged field components to estimate the global configuration of Saturn's magnetic field and map field lines from the equator to Saturn's ionosphere. Within ∼18 …
Overlapping ionospheric and surface echoes observed by the Mars Express radar sounder near the Martian terminator
Gurnett, D. A.; Morgan, D. D.; Duru, F.
Radar soundings from the Mars Express spacecraft occasionally show ionospheric and surface echoes that overlap in frequency. For specular reflection from a horizontally stratified ionosphere such a frequency overlap is not possible, since ionospheric and surface reflections can only occur at frequencies below and above the maximum ionospheric plas…
Can Cassini magnetic field measurements be used to find the rotation period of Saturn's interior?
Bloxham, Jeremy; Sterenborg, M. Glenn
We investigate the determination of the rotation period of Saturn's interior using magnetic field measurements from Cassini. First, we vary the rotation period and search for the period that yields the smallest rms misfit of a magnetic field model to the data. Second, we search for the period that yields the most power in the non-axisymmetric comp…
Cluster observations of outflowing electron distributions and broadband electrostatic emissions above the polar cap
Belmont, G.; Canu, P.; Fontaine, D. +1 more
We investigate the excellent correlation between ionospheric upgoing electron beams and broadband electrostatic emissions (0-6 kHz) observed by Cluster, at ∼5 to 9 Earth's radii above the polar cap. In the absence of detailed, high time resolution waveform data in that region, we precisely analyzed several electron beams to obtain information conc…
Total solar irradiance during the Holocene
Beer, J.; Steinhilber, F.; Fröhlich, C.
For the first time a record of total solar irradiance covering 9300 years is presented, which covers almost the entire Holocene. This reconstruction is based on a recently observationally derived relationship between total solar irradiance and the open solar magnetic field. Here we show that the open solar magnetic field can be obtained from the c…
Radar evidence for ice in lobate debris aprons in the mid-northern latitudes of Mars
Head, James W.; Frigeri, Alessandro; Seu, Roberto +5 more
Subsurface radar sounding data indicate that lobate debris aprons found in Deuteronilus Mensae in the mid-northern latitudes of Mars are composed predominantly of water ice. The position in time delay and the relatively low amount of signal loss of the apparent basal reflectors below the debris aprons indicate that aprons contain only a minor comp…
Solar Irradiance Reference Spectra (SIRS) for the 2008 Whole Heliosphere Interval (WHI)
Chamberlin, Phillip C.; Woods, Thomas N.; Eparvier, Francis G. +6 more
The IHY2007 Whole Heliosphere Interval (WHI) for solar Carrington Rotation 2068 (20 March to 16 April 2008) has been very successful in obtaining a wide variety of solar, heliospheric, and planetary observations during times of solar cycle minimum conditions. One of these efforts is the generation of solar irradiance reference spectra (SIRS) from …
Cassini imaging of Titan's high-latitude lakes, clouds, and south-polar surface changes
West, R. A.; Porco, C. C.; McEwen, A. S. +5 more
Cassini's Imaging Science Subsystem (ISS) has been observing Titan since April 2004, compiling a nearly global surface map and monitoring the surface and atmosphere for activity. Early images of the south-polar region revealed numerous dark surface features and contemporaneous convective cloud systems, suggesting the presence of hydrocarbon lakes …