Rumi Nakamura
Goddard Space Flight Center
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Publication
Featured researches published by Rumi Nakamura.
Journal of Geophysical Research | 1994
Rumi Nakamura; D. N. Baker; T. Yamamoto; R. D. Belian; Edgar A. Bering; J. R. Benbrook; J.R. Theall
The temporal and spatial scales of the onset of two types of substorm events are investigated. These substorms were cases where the expansion onset had precursor localized auroral activation without significant negative bay enhancement, that is, “pseudobreakup”. High-resolution energetic particle and magnetic field data at synchronous orbit are used for the analysis together with auroral and magnetic field data simultaneously taken from ground-based instrumentation. The auroral structure following the pseudobreakup significantly resembled the major expansion aurora, except in its spatial scale. Typical magnetospheric onset signatures such as tail current diversion, dipolarization, and injection were observed associated with some of the pseudobreakups. The major expansion, on the other hand, consisted of a number of rather localized injections and expansions, each of which had timescales of 2-8 min, a comparable timescale to that of pseudobreakups. This study shows that there does not appear to be any phenomenological differences between pseudobreakups and major expansion onsets. The major difference between pseudobreakups and major expansion onsets would be the number of occurrences, as well as the intensity and the scale size of the magnetospheric source.
Journal of Geophysical Research | 1993
Rumi Nakamura; Takasi Oguti; T. Yamamoto; S. Kokubun
Using all-sky TV auroral data with high spatial and temporal resolution, the formation of the auroral bulge is investigated. We show how the discrete auroral structures within the poleward expanding bulge develop systematically toward the west, the east, and also equatorward from a localized breakup region. Auroral structure at the western end of the bulge (a surge) develops with clockwise rotation as viewed along the magnetic field direction. At the eastern part of the bulge, thin auroral features propagate eastward from the breakup region. Around the central meridian of the bulge, auroral features expand equatorward and become north-south aligned (the N-S aurora). The N-S aurora and the eastward propagating aurora develop into diffuse and pulsating aurora after the expansion. We suggest that these discrete auroral structures in the bulge develop along the plasma streamlines in a localized distorted two-cell equipotential distribution; the negative potential peak is concentrated at the western part of the bulge and the positive potential region is spread poleward of the eastward propagating aurora. Equatorward expansion of auroral structures would be attributed in this scenario to the subsequent earthward transport of plasma from the onset region. Energetic particles would also be injected at the N-S auroral region as well as to the east of the region and would trigger the pulsating auroral activity. Poleward expansion, on the other hand, would be produced by the tailward motion of the onset region in accordance with the tailward moving current disruption region.
Archive | 2006
A. A. Petrukovich; W. Baumjohann; Rumi Nakamura; A. Runov; Andre Balogh
Archive | 2010
J. Saito; Toru M. Nakamura; Hidehisa Akiyama; Hirohide Demura; Budi Dermawan; Masato Furuya; Tetsuharu Fuse; Robert W. Gaskell; Takashi Hashimoto; Yusuke Higuchi; Kensuke Hiraoka; Naru Hirata; Chikatoshi Honda; Tetsuya Honda; Motoyuki Ishiguro; Kohei Kitazato; Shingo Kobayashi; Toru Kubota; Naoko Matsumoto; Tatsuhiro Michikami; Hiroyuki Miyamoto; Akiko M. Nakamura; Rumi Nakamura; E. Nemoto; Sho Sasaki; C. Shinohara; Peter W. H. Smith; Akito Sogame; J. Terazono; David J. Tholen
Archive | 2006
Akihiko Fujiwara; Junichiro Kawaguchi; K. Uesugi; D. K. Yeomans; J. Saito; Masanao Abe; Toshiharu Mukai; Masaru Kato; Takashi Okada; Masatoshi Yoshikawa; Hajime Yano; Hirohide Demura; D. Scheers; Robert W. Gaskell; O. S. Barnouin-Jha; Andrew F. Cheng; Hiroyuki Miyamoto; Naru Hirata; Rumi Nakamura; Sho Sasaki; Akiko M. Nakamura
Archive | 2011
K. Uemoto; M. Ohtake; J. Haruyama; Tadashi Matsunaga; Yusuke Yokota; Rumi Nakamura; T. Morota; S. Yamamoto; Shingo Kobayashi; Takahiro Iwata
Archive | 2010
Hiroyuki Takeda; Shingo Kobayashi; Akira Yamaguchi; Mayumi Otsuki; M. Ohtake; J. Haruyama; T. Morota; Yuzuru Karouji; Nobuyuki Hasebe; Rumi Nakamura; Yujiro Ogawa; Tadashi Matsunaga
Archive | 2006
Naru Hirata; O. S. Barnouin-Jha; Chikatoshi Honda; Rumi Nakamura; Akiko M. Nakamura; Hirohide Demura; Tatsuhiro Michikami; Motoyuki Ishiguro; Takashi Hashimoto; Toru Kubota; J. Saito
Archive | 2011
Tadashi Matsunaga; Yusuke Yokota; S. Yamamoto; Rumi Nakamura; M. Ohtake; J. Haruyama
Archive | 2009
Yusuke Yokota; Tadashi Matsunaga; M. Ohtake; J. Haruyama; Yujiro Ogawa; Rumi Nakamura; Chikatoshi Honda; T. Morota; Kazuto Saiki; S. Kawabe; K. Nagasawa; Kohei Kitazato