Anomalous cosmic rays

The solar system is filled with elementary particles of various origins. The dominant source is the Sun and we have extensively discussed in this chapter noble gases from the solar corpuscular radiation (Sun and Moon sections). Here we discuss galactic cosmic ray (GCR) particles, pick-up ions of interstellar or interplanetary origin, and anomalous cosmic rays. A recent overview is provided in a conference proceedings volume (Wimmer-Schweingruber 2001). A summary of the noble gas data is given in Table 13. 

Kulcinski GL, Schmitt HH (1992) Fusion power from lunar resources. Fusion Technology 21 2221-2229 Leske RA, Mewaldt RA, Cummings AC, Cummings JR, Stone EC, von Rosenvinge TT (1996) The isotopic composition of anomalous cosmic rays from Sampex. Space Sci Rev 78 149-154. 

Curiously, there are some nearby interstellar diffuse clouds displaying anomalously low isotope ratios for 7Li/6Li, with a ratio apparently as small as 2 in one case (Lemoine et at. 1994 Knauth, Federman Lambert 2003), compared to the Solar-System (and more usual interstellar) ratio of 12 the anomaly here is that the low ratio in such clouds is consistent with cosmic-ray spallation whereas that in the Solar-System is not. 

LB/10B ratios. That is, the B abundance in the meteoritic sample correlates with extra B. So although itis not possible for elements having but two isotopes to reveal which of the two is anomalous, it is sensible owing to the correlation with B abundance to think ofvaryingadmixtures ofa boron component thatis enriched in 11B. This has been interpreted as a component of boron produced by low-energy cosmic-ray interactions, perhaps even in the presolar cloud or even in the early solar system itself. (See B for more on this.)... 

So far we have summarized some basic reactions starting with the cosmic ray ionization of Hj. However cosmic ray ionization of He, which is considerably less abundant in dense clouds than H2 (about V4) seems to be important for two reasons firstly, an activation energy barrier (Johnsen and Biondi, 1974) is likely to keep the reaction rates of H with H and Hj anomalously small (reaction rate 8 x 10 cm sec Sando et al. 1972), and therefore He remains available for the ionization of neutral molecules. Secondly, in most cases, the charge transfer from He to diatomic molecules dissociates them, producing essentially ionized heavy elements, such as C, N , O". The reaction sequence has the general form (see note added in proof). 

Jokipii JR (1990) The anomalous components of cosmic rays. In Physics of the outer heliosphere. 

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