Search Publications
Venusian middle-atmospheric dynamics in the presence of a strong planetary-scale 5.5-day wave
Yamamoto, Masaru; Takahashi, Masaaki
The middle atmospheric dynamics on Venus are investigated using a middle atmosphere general circulation model. The magnitude of the superrotation is sensitive to the amplitude of the planetary-scale waves. In particular, the critical level absorptions of the forced planetary-scale waves might contribute to the maintenance of the superrotation near…
Ground-based and spacecraft observations of lightning activity on Saturn
Schneider, J.; Cecconi, B.; Fischer, G. +21 more
In late 2007, Saturn electrostatic discharges (SED) were simultaneously observed at the radio telescope UTR-2 and with the Cassini spacecraft. Observations at UTR-2 were performed with a multichannel receiver in the frequency range 12-33 MHz, and those performed on Cassini-with a swept frequency receiver that is part of the RPWS (Radio and Plasma …
White-Light Observations and Polarimetric Analysis of the Solar Corona During the Eclipse of 1 August 2008
Skomorovsky, V. I.; Trifonov, V. D.; Mashnich, G. P. +4 more
In order to study the solar corona during eclipses, a new telescope was constructed. Three coronal images were obtained simultaneously through a single objective of the telescope as the coronal radiation passed through three polarizers (whose transmission directions were turned 0°, 60°, and 120° in the chosen direction); one image was obtained wit…
Coronal Mass Ejections and the Index of Effective Solar Multipole
Obridko, V. N.; Yurchyshyn, V. B.; Ivanov, E. V. +2 more
The paper considers the relationship between the cyclic variations in the velocity of coronal mass ejections (CME) and the large-scale magnetic field structure (LSMF) in cycles 21 - 23. To characterize a typical size of the LSMF structure, we have used the index of the effective solar multipole (ESMI). The cyclic behavior of the CME occurrence rat…
Discovery of multiple shells around the planetary nebula IC 418
Guerrero, M. A.; Ramos-Larios, G.; Bravo-Alfaro, H. +3 more
We have analysed optical, near- and mid-IR images of the bright planetary nebula (PN) IC 418. These images probe unambiguously for the first time a number of low surface brightness structures and shells around the bright main nebula, including radial filaments or rays, a system of three concentric rings and two detached haloes with sizes ∼150 arcs…
Scalings, Cascade and Intermittency in Solar Wind Turbulence
Carbone, Vincenzo
Investigating in situ fluctuations in the interplanetary space, offers us a unique challenge to study scaling properties in a turbulent medium which cover a wide range of scales. This includes not only the inertial range, where turbulence can be described within a fluid-like approach, but also the high-frequency region, where a kinetic approach is…
Nonaxisymmetric Anisotropy of Solar Wind Turbulence as a Direct Test for Models of Magnetohydrodynamic Turbulence
Chapman, S. C.; Turner, A. J.; Gogoberidze, G.
Single point spacecraft observations of the turbulent solar wind flow exhibit a characteristic nonaxisymmetric anisotropy that depends sensitively on the perpendicular power spectral exponent. We use this nonaxisymmetric anisotropy as a function of wave vector direction to test models of MHD turbulence. Using Ulysses magnetic field observations in…
Hubble Space Telescope FUV Spectra of the Post-common-envelope Hyades Binary V471 Tauri
Bond, Howard E.; Sion, Edward M.; Godon, Patrick +4 more
We have carried out an analysis of the Hubble Space Telescope (HST)/STIS archival spectra of the magnetic white dwarf (WD) in the Hyades eclipsing-spectroscopic, post-common-envelope binary V471 Tauri, time resolved on the orbit and on the X-ray rotational phase of the magnetic WD. An HST/STIS spectrum obtained during primary eclipse reveals a hos…
Empirical Estimates of Martian Surface Pressure in Support of the Landing of Mars Science Laboratory
Withers, Paul
The aim of this work is to develop an empirical expression for diurnal mean martian surface pressure in support of the landing of Mars Science Laboratory. We evaluate the consistency of surface pressure measurements from four landers, Viking Lander 1, Viking Lander 2, Mars Pathfinder, and Phoenix, and one radio occultation experiment, Mars Global …
Observations of oxygen ions in the dayside magnetosheath associated with southward IMF
Nilsson, H.; Slapak, R.; Eriksson, A. +1 more
We present a case study of high energy oxygen ions (O+) observed in the dayside terrestrial magnetosheath, in the southern hemisphere. It is shown that the presence of O+ is strongly correlated to the IMF direction: O+ is observed only for Bz < 0. Three satellites observe O+ immediately at …