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In Earth's environment, the observed polar outflow rate for O(+) ions, the main source of oxygen above gravitational escape energy, corresponds to the loss of approximately 18% of the present-day atmospheric oxygen over 3 billion years. However, part of this apparent loss can actually be returned to the atmosphere. Examining loss rates of four escape routes(More)
Characteristic scale lengths of nonthermal X-rays from the SN 1006 NE rim, which are observed by Chandra, are interpreted in the context of the diffusive shock acceleration on the assumption that the observed spatial profile of nonthermal X-rays corresponds to that of accelerated electrons with energies of a few tens of TeV. To explain the observed scale(More)
The massive flare of 27 December 2004 from the soft gamma-ray repeater SGR 1806-20, a possible magnetar, saturated almost all gamma-ray detectors, meaning that the profile of the pulse was poorly characterized. An accurate profile is essential to determine physically what was happening at the source. Here we report the unsaturated gamma-ray profile for the(More)
The outer shells of young supernova remnants (SNRs) are the most plausible acceleration sites of high-energy electrons with the diffusive shock acceleration (DSA) mechanism. We studied spatial and spectral properties close to the shock fronts in four historical SNRs (Cas A, Kepler's remnant, Tycho's remnant, and RCW 86) with excellent spatial resolution of(More)
Particle acceleration is one of the most important topics in plasma astrophysics as well as in cosmic-ray astrophysics. The heliosphere is an ideal astrophysical laboratory, wherein one can observe in situ the elementary mechanisms involved in the particle acceleration processes. Two phenomena of special interest are stochastic acceleration in the(More)
On December 27, 2004, plasma particle detectors on the GEOTAIL spacecraft detected an extremely strong signal of hard X-ray photons from the giant flare of SGR1806-20, a magnetar 1,2 candidate. While practically all gamma-ray detectors on any satellites were saturated during the first ∼500 ms interval after the onset, one of the particle detectors on(More)
Most visible matter in the Universe exists as plasma. How this plasma is heated, and especially how the initial non-equilibrium plasma distributions relax to thermal equilibrium (as predicted by Maxwell-Boltzman statistics), is a fundamental question in studies of astrophysical and laboratory plasmas. Astrophysical plasmas are often so tenuous that binary(More)
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