On the Low Energy Spectrum of Primary Cosmic Radiation and the Sun's Magnetic Dipole Moment

1949 ◽  
Vol 76 (12) ◽  
pp. 1889-1890 ◽  
Author(s):  
M. A. Pomerantz ◽  
M. S. Vallarta
Author(s):  
Andrew J Coates

Titan is the only Moon in the Solar System with a significant permanent atmosphere. Within this nitrogen–methane atmosphere, an ionosphere forms. Titan has no significant magnetic dipole moment, and is usually located inside Saturn's magnetosphere. Atmospheric particles are ionized both by sunlight and by particles from Saturn's magnetosphere, mainly electrons, which reach the top of the atmosphere. So far, the Cassini spacecraft has made over 45 close flybys of Titan, allowing measurements in the ionosphere and the surrounding magnetosphere under different conditions. Here we review how Titan's ionosphere and Saturn's magnetosphere interact, using measurements from Cassini low-energy particle detectors. In particular, we discuss ionization processes and ionospheric photoelectrons, including their effect on ion escape from the ionosphere. We also discuss one of the unexpected discoveries in Titan's ionosphere, the existence of extremely heavy negative ions up to 10 000 amu at 950 km altitude.


2020 ◽  
Vol 102 (10) ◽  
Author(s):  
Danielle R. Yahne ◽  
Liurukara D. Sanjeewa ◽  
Athena S. Sefat ◽  
Bradley S. Stadelman ◽  
Joseph W. Kolis ◽  
...  

2009 ◽  
Vol 5 (S264) ◽  
pp. 385-394 ◽  
Author(s):  
J.-M. Grießmeier ◽  
M. Khodachenko ◽  
H. Lammer ◽  
J. L. Grenfell ◽  
A. Stadelmann ◽  
...  

AbstractStellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.


1988 ◽  
Vol 37 (5) ◽  
pp. 1142-1152 ◽  
Author(s):  
D. W. Hertzog ◽  
M. Eckhause ◽  
P. P. Guss ◽  
D. Joyce ◽  
J. R. Kane ◽  
...  

1947 ◽  
Vol 71 (7) ◽  
pp. 393-398 ◽  
Author(s):  
M. S. Vallarta ◽  
M. L. Perusquía ◽  
J. de Oyarzábal

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