The composition of galactic cosmic rays and solar energetic particles

Mason, G. M.

doi:10.1029/rg025i003p00685

Cited by 21 publications

(6 citation statements)

References 96 publications

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“…In brief, the analysis showed a consistent dependence of heavy ion abundances on A/Z (the atomic weight to charge ratio). The only deviation from this A/Z ordering has been found in alpha particle behavior and in the behavior of protons themselves (Meyer, 1985;Mason, 1987). Attempts to explain this deviation by DSA models required artificially high injection rates in order for the results to be at least qualitatively consistent with observations Ng et al, 1999).…”

Section: Introductionsupporting

confidence: 54%

Heavy ion acceleration at parallel shocks

Galinsky

Shevchenko

2010

Nonlin. Processes Geophys.

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Abstract.A study of alpha particle acceleration at parallel shock due to an interaction with Alfvén waves self-consistently excited in both upstream and downstream regions was conducted using a scale-separation model Shevchenko, 2000, 2007). The model uses conservation laws and resonance conditions to find where waves will be generated or damped and hence where particles will be pitch-angle scattered. It considers the total distribution function (for the bulk plasma and high energy tail), so no standard assumptions (e.g. seed populations, or some ad-hoc escape rate of accelerated particles) are required. The heavy ion scattering on hydromagnetic turbulence generated by both protons and ions themselves is considered. The contribution of alpha particles to turbulence generation is important because of their relatively large massloading parameter P α = n α m α /n p m p (m p , n p and m α , n α are proton and alpha particle mass and density) that defines efficiency of wave excitation. The energy spectra of alpha particles are found and compared with those obtained in test particle approximation.

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Section: Introductionsupporting

confidence: 54%

Heavy ion acceleration at parallel shocks

Galinsky

Shevchenko

2010

Nonlin. Processes Geophys.

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“…This shadowing effect is illustrated by the sketch in Figure 14. Flares also generate heavy ions with a composition that is in rough proportion to the solar abundance [e.g., Mason, 1987] shock waves, which either accompany plasma cloud ejections from flare sites or are produced when solar wind streams of different speeds interact, also accelerate particles, but they are generally less energetic than those produced by flares. Nevertheless, their more frequent occurrence (in the case of stream interaction regions, several times every ~27-day solar rotation at Earth) makes them noteworthy.…”

Section: The Energetic Particle Environmentmentioning

confidence: 99%

Near‐Mars space

Luhmann¹,

Brace²

1991

Reviews of Geophysics

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The space environment of Mars is largely determined by its lack of a substantial planetary magnetic field. In contrast to Earth, Mars does not have radiation belts or an auroral "oval," and its perturbation of the interplanetary medium or solar wind is confined to a relatively small volume. Moreover, the direct interaction of the solar wind plasma with the Martian atmosphere produces a distinctive local energetic particle population of planetary origin, which provides evidence of the possibly significant scavenging of certain elements from Mars over the life of the solar system. In this paper we describe the general characteristics of near-Mars space, as it is known today, including both the ambient interplanetary environment and the ionosphere, upper atmosphere, and regions above that are affected by the presence of Mars. the shock formation were used to infer that the "nose" of the Martian obstacle to the solar wind cotfid be no more than a few hundred kilometers above the surface [e.g., Smith et al., 1965;Dryer and Heckman, 1967;Spreiter and Rizzi, 1972;Slavin and Holzer, 1982]. However, those spacecraft which were equipped with the appropriate particle and field detectors never flew close enough to determine whether an Earthlike magnetopause existed at such a low altitude.

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“…It was not until the advent of the space age that direct observations of the spectra and composition of solar particle events were accomplished routinely (see Gloeckler [1979], Cook et al [1984], McGuire et al [1986] and Mason [1987] for recent results and reviews). Coincidentally, the adverse effects of solar particle events on electronic subsystems on satellites and health considerations for humans in space represented important practical needs for acquiring detailed knowledge of the characteristics of these events and for developing estimates of "worst case" environments.…”

Section: Solar Particle Eventsmentioning

confidence: 99%

Solar cycle effects on the near‐Earth space environment

Gorney¹

1990

Reviews of Geophysics

107

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Forecasts of the magnitude of solar activity in the 1990s (solar cycle 22) imply that the expected levels of activity might be some of the most extreme ever recorded, and almost certainly the levels of activity will be the highest experienced during the space age. Even as early as 1 year before the expected maximum of solar cycle 22 in 1990, unprecedented levels of solar activity (for example, the solar flares and solar particle events of August -October 1989) and geomagnetic activity (for example, the auroral events and geomagnetic storms of March 1989) have been observed. These solar and geophysical events have stirred scientific interest both in the long-term behavior'of solar activity and in the physics which couples the energy of solar events to the near-Earth environment. Furthermore, the operational community (including those involved in satellite operations, telephone and radio communication, electric power distribution, aviation, and others) have experienced many adverse effects of these solar and geophysical events. Many more episodes of activity are expected throughout the upcoming 4-5 years. The purpose of this paper is to review the direct and indirect influences of solar activity on the near-Earth environment and to describe some of the implications of the high levels of solar activity which are expected to occur in the 1990-1994 time period. INTRODUCTION The regular variation of solar activity, which has come to be known as the 11-year sunspot cycle, was discovered in the mid-nineteenth century [Schwabe, 1843], although documented scientific observations of the existence of cyclic behavior extend as far back as the invention of the telescope in the seventeenth century [see Galilei, 1957]. Perhaps the earliest recorded physical effects of solar activity on man were intermittent telegraph outages in the late 1850s [Maggs, 1988], although it was not until the 1940s that systematic scientific observations of particulate emissions from the Sun were made at Earth [e.g., Forbush, 1946; Forbush et al., 1950] (also see Lovell [1987] and Smart and Shea [1989]). A historic record of sunspot activity, including data through 1989, is shown in Figure 1. Solar physicists have predicted that the upcoming maximum of solar activity, scheduled to occur in 1990, might be the most extreme ever recorded [e.g., Hirman et al., 1988; Kane, 1987; Lantos and Simon, 1987; Schatten and Sofia, 1987; Thompson, 1988; Withbroe, 1989]. Extreme levels of solar and geomagnetic activity observed in 1989 seem to confirm these predictions [see Allen et al., 1989]. A power outage in eastern Canada caused by an extreme geomagnetic event in March 1989 (affecting approximately 6 million people for over 9 hours) speaks to the practical importance of these phenomena. It seems certain, on the basis of the observed rate of increase in solar activity starting with the most recent minimum in September 1986 (the start of solar cycle 22), that the upcoming solar maximum will be the most severe of those which have occurred during the space age (i.e....

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The composition of galactic cosmic rays and solar energetic particles

Cited by 21 publications

References 96 publications

Heavy ion acceleration at parallel shocks

Heavy ion acceleration at parallel shocks

Near‐Mars space

Solar cycle effects on the near‐Earth space environment

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