EFFECTS OF LEAKAGE NEUTRAL PARTICLES ON SHOCKS

Journal Article · Sat Oct 20 04:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/758/2/97· OSTI ID:22086533

Ohira, Yutaka ^[1]

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1. Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258 (Japan)

In this paper, we investigate effects of neutral particles on shocks propagating into the partially ionized medium. We find that for 120 km s{sup -1} < u {sub sh} < 3000 km s{sup -1} (u {sub sh} is the shock velocity), about 10% of upstream neutral particles leak into the upstream region from the downstream region. Moreover, we investigate how the leakage neutral particles affect the upstream structure of the shock and particle accelerations. Using four-fluid approximations (upstream ions, upstream neutral particles, leakage neutral particles, and pickup ions), we provide analytical solutions of the precursor structure due to leakage neutral particles. It is shown that the upstream flow is decelerated in the precursor region and the shock compression ratio becomes smaller than without leakage neutral particles, but the total compression ratio does not change. Even if leakage of neutral particles is small (a few percent of total upstream particles), this smaller compression ratio of the shock can explain steep gamma-ray spectra from young supernova remnants. Furthermore, leakage neutral particles could amplify the magnetic field and heat the upstream region.

• OSTI ID: 22086533
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 758; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
ANALYTICAL SOLUTION
APPROXIMATIONS
ASTRONOMY
ASTROPHYSICS
COMPRESSION RATIO
COSMIC RADIATION
GAMMA SPECTRA
INTERSTELLAR MAGNETIC FIELDS
NEUTRAL PARTICLES
PLASMA FLUID EQUATIONS
SHOCK WAVES
SUPERNOVA REMNANTS