Geometry of an interplanetary CME on October 29, 2003 deduced from cosmic rays

Kuwabara, T.; Munakata, K.; Yasue, S.; Kato, C.; Akahane, S.; Koyama, M.; Bieber, J. W.; Evenson, P. A.; Pyle, R.; Fujii, Z.; Tokumaru, M.; Kojima, M.; Marubashi, K.; Duldig, M. L.; Humble, J. E.; Silva, M. R.; Trivedi, N. B.; González, W. D.; Schuch, Nelson Jorge

doi:10.1029/2004gl020803

Cited by 36 publications

(50 citation statements)

References 6 publications

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“…Further, we repeated the calculations using unfiltered data and find that the final results are not significantly different. There can also be anisotropies intrinsic to the CME/magnetic cloud itself, arising from a B×∇ N drift, where B is the interplanetary magnetic field and ∇ N denotes the cosmic-ray density gradient inside the CME (Bieber & Evenson 1998;Munakata et al 2003Munakata et al , 2005Kuwabara et al 2004). Such anisotropies can potentially be "mixed" with the diurnal anisotropy, and it is possible that there will still be some residual anisotropy after the filter is applied.…”

Section: Discussionmentioning

confidence: 99%

“…In this case since the magnitude of Forbush decrease is comparatively small, the diurnal variations are comparable to the decrease, and it is not possible to fit the unfiltered data to obtain any meaningful estimates for the parameters of the Forbush decrease; hence, it is necessary to only use the filtered data for this purpose. Furthermore, it is very likely that there is some CME-related anisotropy remaining in the data, and removing it requires the technique used by Munakata et al (2003Munakata et al ( , 2005 and Kuwabara et al (2004), which is outside the scope of the current paper.…”

Section: Magnetic Cloud Datamentioning

confidence: 99%

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Forbush decreases and turbulence levels at coronal mass ejection fronts

Subramanian

Antia

Dugad

et al. 2008

A&A

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Aims. We seek to estimate the average level of MHD turbulence near coronal mass ejection (CME) fronts as they propagate from the Sun to the Earth. Methods. We examined the cosmic ray data from the GRAPES-3 tracking muon telescope at Ooty, together with the data from other sources for three closely observed Forbush decrease events. Each of these event is associated with frontside halo coronal mass ejections (CMEs) and near-Earth magnetic clouds. The associated Forbush decreases are therefore expected to have significant contributions from the cosmic-ray depressions inside the CMEs/ejecta. In each case, we estimate the magnitude of the Forbush decrease using a simple model for the diffusion of high-energy protons through the largely closed field lines enclosing the CME as it expands and propagates from the Sun to the Earth. The diffusion of high-energy protons is inhibited by the smooth, large-scale magnetic field enclosing the CME and aided by the turbulent fluctuations near the CME front. We use estimates of the cross-field diffusion coefficient D ⊥ derived from the published results of extensive Monte Carlo simulations of cosmic rays propagating through turbulent magnetic fields. We then compare our estimates with the magnitudes of the observed Forbush decreases. Results. Our method helps constrain the ratio of energy density in the turbulent magnetic fields to that in the mean magnetic fields near the CME fronts. This ratio is found to be ∼2% for the 2001 April 11 Forbush decrease event, ∼6% for the 2003 November 20 Forbush decrease event and ∼249% for the much more energetic event of 2003 October 29.

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Section: Discussionmentioning

confidence: 99%

Section: Magnetic Cloud Datamentioning

confidence: 99%

Forbush decreases and turbulence levels at coronal mass ejection fronts

Subramanian

Antia

Dugad

et al. 2008

A&A

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“…Smooth rotations of the magnetic field direction began to be observed at the time of the first vertical dashed line [see also Kuwabara et al, 2004]. Furthermore, at that time, there is a change in B from high to low variance in both magnitude and direction, a typical magnetic field signature of ejecta [e.g., Gosling, 1997], as well as a decrease in the $MeV ion intensity [e.g., Richardson, 1997].…”

Section: First Icme 29-30 October 2003mentioning

confidence: 99%

“…[15] Kuwabara et al [2004] used cosmic ray and magnetic field observations to derive the three-dimensional geometry of this ICME. The period of cosmic ray depleted intensity that best fits their model extended only 6 hours, from 1300 UT to 1900 UT on 29 October.…”

Section: First Icme 29-30 October 2003mentioning

confidence: 99%

October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations

et al. 2005

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[1] In late October and early November 2003 the ACE spacecraft at 1 AU detected two shock-associated interplanetary coronal mass ejections (ICMEs). In the sheath region formed in front of both ICMEs, some of the highest speeds ever directly measured in the solar wind were observed. We analyze in detail the energetic particle signatures measured at 1 AU by the EPAM experiment on board ACE during the passage and in the vicinity of these ICMEs. Solar energetic particles (SEPs) are utilized as diagnostic tracers of the large-scale structure and topology of the interplanetary magnetic field (IMF) embedded within both ICME events. In order to explain the bidirectional particle flows observed within both ICMEs, we have examined two candidate scenarios for these ICMEs in terms of open and closed magnetic field configurations. In the context of an open field configuration, the enhanced magnetic field regions associated with the CME-driven shocks mirror the energetic particles and hence the observed bidirectional flows. In the context of a closed field configuration, bidirectional flows result from particle circulation and reflection in a looped field configuration. Furthermore, we use the ACE/EPAM observations to reassess the leading and trailing boundaries of the ICMEs with respect to those previously proposed based upon ACE/SWEPAM solar wind plasma, suprathermal electron measurements, and ACE/MAG magnetic field data.

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“…The data analysis method based on this equation has been shown to be valid, useful and successful in several previous papers (Kuwabara et al 2004;Munakata et al 2005;Okazaki et al 2008;Fushishita et al 2010;Rockenbach et al 2011Rockenbach et al , 2014Kozai et al 2014Kozai et al , 2016. The derived anisotropy vector t GEO x ( ) in the GEO coordinate system is then transformed to t GSE x ( ) in the geocentric solar ecliptic (GSE) coordinate system for comparisons with the solar wind and IMF data.…”

Section: T I T C T C T S T T S T C T T Cmentioning

confidence: 99%

Cosmic-Ray Short Burst Observed with the Global Muon Detector Network (GMDN) on 2015 June 22

Munakata

Kozai

Evenson

et al. 2018

ApJ

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We analyze the short cosmic-ray intensity increase ("cosmic-ray burst": CRB) on 2015 June 22 utilizing a global network of muon detectors and derive the global anisotropy of cosmic-ray intensity and the density (i.e., the omnidirectional intensity) with 10 minute time resolution. We find that the CRB was caused by a local density maximum and an enhanced anisotropy of cosmic rays, both of which appeared in association with Earth's crossing of the heliospheric current sheet (HCS). This enhanced anisotropy was normal to the HCS and consistent with a diamagnetic drift arising from the spatial gradient of cosmic-ray density, which indicates that cosmic rays were drifting along the HCS from the north of Earth. We also find a significant anisotropy along the HCS, lasting a few hours after the HCS crossing, indicating that cosmic rays penetrated into the inner heliosphere along the HCS. Based on the latest geomagnetic field model, we quantitatively evaluate the reduction of the geomagnetic cutoff rigidity and the variation of the asymptotic viewing direction of cosmic rays due to a major geomagnetic storm that occurred during the CRB and conclude that the CRB is not caused by the geomagnetic storm, but by a rapid change in the cosmic-ray anisotropy and density outside the magnetosphere.

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Geometry of an interplanetary CME on October 29, 2003 deduced from cosmic rays

Cited by 36 publications

References 6 publications

Forbush decreases and turbulence levels at coronal mass ejection fronts

Forbush decreases and turbulence levels at coronal mass ejection fronts

October/November 2003 interplanetary coronal mass ejections: ACE/EPAM solar energetic particle observations

Cosmic-Ray Short Burst Observed with the Global Muon Detector Network (GMDN) on 2015 June 22

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