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ACRIM-gap and total solar irradiance revisited: Is there a secular trend between 1986 and 1996?
Solanki, S. K.; Krivova, N. A.; Wenzler, T.
A gap in the total solar irradiance (TSI) measurements between ACRIM-1 and ACRIM-2 led to the ongoing debate on the presence or not of a secular trend between the minima preceding cycles 22 (in 1986) and 23 (1996). It was recently proposed to use the SATIRE model of solar irradiance variations to bridge this gap. When doing this, it is important t…
Dual periodicities in energetic electrons at Saturn
Krupp, N.; Krimigis, S. M.; Mitchell, D. G. +1 more
The fluxes of energetic electrons (110-365 keV) in Saturn's magnetosphere were subjected to Lomb periodogram analyses for 1677 days from late 2004 to the middle of 2009. The electrons generally exhibited strong periodicities at 10.82 hours and 10.60 hours for much of the ∼4.6 year interval. The longer period was generally present all the time, whi…
Regions associated with electron physics in asymmetric magnetic field reconnection
Pritchett, P. L.; Mozer, F. S.
Spatial relationships between regions containing signatures of electron physics in asymmetric reconnection with a guide field are examined using simulations and space observations that are in excellent agreement. These electron physics regions do not completely overlap, are not confined to sizes ∼electron skin depth, and do not surround the X-line…
On the elusive hot oxygen corona of Venus
Lammer, H.; Shematovich, V. I.; Lichtenegger, H. I. M. +2 more
After more than two years in orbit still no Venus Express observations were published concerning the hot oxygen corona of Venus which could verify the corresponding controversial observations of Venera 11 and PVO, three decades ago. Based on recent energy and mass dependent collision cross sections, the energy distributions of hot atomic oxygen cr…
Plume ionosphere of Enceladus as seen by the Cassini ion and neutral mass spectrometer
Luhmann, J. G.; Ip, W. -H.; McNutt, R. L. +4 more
The Cassini spacecraft passed within 168 km of the surface of Enceladus on 14 July 2005 during the E2 flyby and passed closer (50 km) during the E3 encounter on 13 March 2008. During both flybys the ion and neutral mass spectrometer (INMS) detected a plume atmosphere mainly composed of water. During the E3 flyby, the INMS measured an ion mass spec…
Vortex circulation on Venus: Dynamical similarities with terrestrial hurricanes
Piccioni, Giuseppe; Markiewicz, Wojciech J.; Limaye, Sanjay S. +3 more
Some dynamical and morphological similarities exist between the vortex organization of the atmosphere in the northern and southern hemispheres of Venus and the tropical cyclones/hurricanes on Earth. An S-shape feature detected in the center of the vortices on Venus from Pioneer Venus Orbiter and Venus Express observations has also been seen in tro…
Reconstructed and measured total solar irradiance: Is there a secular trend between 1978 and 2003?
Solanki, S. K.; Krivova, N. A.; Wenzler, T.
Total solar irradiance reconstructed between 1978 and 2003 using solar surface magnetic field distributions is compared with three composites of total solar irradiance measurements. A good correspondence is found with the total solar irradiance composite from PMOD/WRC, with no bias between the three cycles. The agreement with the other composites …
Long-lived auroral structures and atmospheric losses through auroral flux tubes on Mars
Barabash, S.; Lundin, R.; Woch, J. +2 more
The ASPERA-3 observations of electron and ion fluxes over the regions dominated by crustal magnetic fields show the existence of long-lived and active aurora-type magnetic flux tubes with a width of 20-150 km. The activity manifests itself by large electron energy fluxes (≥10-4 W/m2) and strong distortions in the upper (350-4…
Is the Martian water table hidden from radar view?
Gurnett, D. A.; Farrell, W. M.; Plaut, J. J. +4 more
Mars may possess a global sub-surface groundwater table as an integral part of its current hydrological system. However, the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) onboard the Mars Express (MEx) spacecraft has yet to make a definitive detection of such a body of liquid water. In this work, we quantify the conditions t…
Stochastic and direct acceleration mechanisms in the Earth's magnetotail
Perri, S.; Zimbardo, G.; Greco, A.
Ion beams with energies of the order of several tens of keV are frequently observed in the Earth's magnetotail. Here we consider two possible acceleration mechanisms, the cross tail electric field E y and the stochastic acceleration due to the electromagnetic fluctuations present in the magnetotail. Electromagnetic perturbations are g…