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Average features of the interplanetary shock observed with the Global Muon Detector Network
Citation
Kozai, M and Munakata, K and Kato, C and Kuwabara, T and Rockenbach, M and Dal Lago, A and Schuch, NJ and Al Jassar, HK and Sharma, MM and Duldig, ML and Humble, JE and Bieber, JW and Evenson, P and Sabbah, I and Tokumaru, M, Average features of the interplanetary shock observed with the Global Muon Detector Network, Proceedings of Science, 30 July - 06 August, The Hague, Netherlands, pp. 1-8. ISSN 1824-8039 (2015) [Non Refereed Conference Paper]
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Abstract
From three-dimensional spatial density gradient of galactic cosmic rays (GCRs) observed with the
Global Muon Detector Network (GMDN), we derive average features of the GCR depleted region
behind the IP (interplanetary) shock. We identify 207 IP-shocks that passed the earth based on the
geomagnetic storm sudden commencements (SSCs) and extract 50 events that are associated with
solar coronal mass ejections (CMEs) in a period between 2006 and 2014. From the first order
GCR anisotropy corrected for the solar wind convection and Compton-Getting effect arising from
the earth’s orbital motion, we deduce the density gradient on an hourly basis for each event. We
then derive the average temporal variation of the density gradient by superposing its variations
at the SSC onset timing. We confirm that the density gradient components are clearly enhanced
after the shock passage, indicating the existence of GCR depleted region behind the shock which
causes the Forbush Decrease in the cosmic ray intensity. The enhancement of the radial gradient
shows longer duration when the earth has encountered the western flank of the shock, implying
an asymmetric shielding effect of the shock on the GCRs. The longitudinal gradient, on the other
hand, shows that the GCR density minimum is located around the longitudinal center behind the
shock, which can be ascribed to the centered ejecta driving IP-shock.
Item Details
| Item Type: | Non Refereed Conference Paper |
|---|---|
| Keywords: | cosmic rays: ICME, shocks, Forbush decreases |
| Research Division: | Physical Sciences |
| Research Group: | Astronomical sciences |
| Research Field: | High energy astrophysics and galactic cosmic rays |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding knowledge |
| Objective Field: | Expanding knowledge in the physical sciences |
| UTAS Author: | Duldig, ML (Dr Marc Duldig) |
| UTAS Author: | Humble, JE (Dr John Humble) |
| ID Code: | 110301 |
| Year Published: | 2015 |
| Deposited By: | Mathematics and Physics |
| Deposited On: | 2016-07-23 |
| Last Modified: | 2016-08-05 |
| Downloads: | 0 |
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