A Caltech Library Service

Anomalous Cosmic Rays: Interstellar Interlopers in the Heliosphere and Magnetosphere

Mewaldt, R. A. and Cummings, A. C. and Stone, E. C. (1994) Anomalous Cosmic Rays: Interstellar Interlopers in the Heliosphere and Magnetosphere. Eos, 75 (16). pp. 185-193. ISSN 0096-3941.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Since the beginning of the space age, it was known that two main sources of energetic particles pervade interplanetary space: galactic cosmic rays (GCRs), which originate in sources outside the solar system, and solar energetic particles (SEPs), associated with transient events on the Sun. But over 20 years ago, instruments on the Pioneer 1O, IMP 5, and IMP 7 spacecraft discovered a third component of energetic particles known as "anomalous cosmic rays," that represents a sample of nearby interstellar material. Over the past 2 decades, ACRs have been used to study the acceleration and transport of energetic particles within the solar system, deduce the global properties of the heliosphere- the bubble of solar wind that envelopes the solar system, and study the interstellar material itself. It has recently been shown that some of these ACRs have become trapped in Earth's magnetic field, where they form a radiation belt composed of interstellar material (Figure I). Also, ACRs are being used to address a question that has existed ever since the discovery of the solar wind: "How large is the heliosphere?"

Item Type:Article
Related URLs:
URLURL TypeDescription
Mewaldt, R. A.0000-0003-2178-9111
Cummings, A. C.0000-0002-3840-7696
Stone, E. C.0000-0002-2010-5462
Additional Information:Copyright 1994 by the American Geophysical Union.
Group:Space Radiation Laboratory
Non-Subject Keywords:Cosmic Rays, Earth Magnetosphere, Heliosphere, Interstellar Matter, Heavy Nuclei, Radiation Belts, Solar Probes, Space Missions
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1993-38
Issue or Number:16
Record Number:CaltechAUTHORS:20140516-132152344
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:45810
Deposited By: Deborah Miles
Deposited On:15 Jun 2014 17:48
Last Modified:20 Feb 2020 14:33

Repository Staff Only: item control page