TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 61 (No. 5), pp. 555-559, 2009


A two-step scenario for both solar flares and magnetospheric substorms: Short duration energy storage

Bruce T. Tsurutani1, Kazunari Shibata2, Syun-Ichi Akasofu3, and Mitsuo Oka4

1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA
2Kyoto University, Kyoto, Japan
3International Arctic Research Center (IARC), Univ. Alaska, Fairbanks, AK
4University of Alabama in Huntsville, Huntsville, AL

(Received September 16, 2008; Revised February 25, 2009; Accepted March 12, 2009; Online published May 29, 2009)

Abstract: The basic observations for magnetic storms and substorms at Earth and for flares at the Sun are reviewed for background. We present a common scenario of double magnetic reconnection for both substorms and flares based on previous interplanetary observations and substorm-triggering results. Central to the scenario is that the first magnetic reconnection phase is the source of energy loading for possible substorms and flares. The energy placed in the magnetotail or magnetosphere/at the sun lasts for only a short duration of time however. The energy gets dissipates away rapidly (in some less dramatic form). This scenario predicts that if the initial reconnection process is sufficiently intense and rapid, concomitant substorms and flares occur soon thereafter. If the energy input is less rapid, there may be lengthy delays for the onset of substorms and flares. If external influences (shocks, etc.) occur during the latter energy buildup, the "trigger" will cause a sudden release of this energy. The model also explains reconnection without subsequent substorms and flares. The model addresses the question why strong triggering events are sometimes ineffective.
Key words: Solar flares, substorms, magnetic storms, magnetic reconnection.

Corresponding author E-mail: bruce.tsurutani@jpl.nasa.gov

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