The solar energetic particle event of 16 August 2001: ~ 400 MeV protons following an eruption at ~ W180

E. W. Cliver, B. J. Thompson, G. R. Lawrence, A. N. Zhukov, A. J. Tylka, W. F. Dietrich, D. V. Reames, M. J. Reiner, R. J. MacDowall, A. G. Kosovichev, A. G. Ling

Research output: Contribution to conferencePaperpeer-review

25 Scopus citations


A fast ( ~ 1500 km s-1 ) full-halo coronal mass ejection (CME) was observed late on 15 August 2001 by the white-light coronagraph on SOHO, and was followed within an hour by an intense 400 MeV proton event at 1 AU. The absence of significant front side activity at the inferred launch time of the CME indicates a source region on the far side of the Sun. The most promising active region to produce a major CME on 15-16 August was AR 9557, located near the far side disk center. Supporting evidence for this extreme back side CME origin is provided by helioseismology analysis of Michelson Doppler Imager (MDI) data and from analysis of the trajectories of low-frequency (< 1 MHz) radio bursts observed by experiments on Ulysses andWind. Extreme ultra-violet Imaging Telescope (EIT) images reveal the onset of activity at the west limb of the Sun, suggesting the arrival of a wave front near the time that the first solar energetic particles (SEPs) to arrive at Earth were injected into space. We interpret these observations in terms of widespread acceleration of SEPs at a coronal shock wave that is manifested by a Wind/WAVES decametric/hectometric (DH) type II radio burst.

Original languageEnglish (US)
Number of pages4
StatePublished - 2005
Externally publishedYes
Event29th International Cosmic Ray Conference, ICRC 2005 - Pune, India
Duration: Aug 3 2005Aug 10 2005


Other29th International Cosmic Ray Conference, ICRC 2005

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics


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