Is Substorm Occurrence a Necessary Condition for a Magnetic Storm?

Kamide, Y.

doi:10.5636/jgg.44.109

Cited by 83 publications

(65 citation statements)

References 22 publications

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“…For about two decades some of our colleagues have been saying that the sub-storm hypothesis, which is that a magnetic storm is composed of a series of substorms, is too simplistic if not false (for an early instance, see Kamide, 1980; for a strong version of this position, see Kamide, 1992; for a review, see Gonzalez et al, 1994). An observation bearing on this issue was recently reported.…”

Section: Must a Substorm Be A Sub-storm?mentioning

confidence: 99%

On storm weakening during substorm expansion phase

Siscoe

Petschek

1997

Ann Geophysicae

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Abstract. Iyemori and Rao recently presented evidence that the strength of a magnetic storm, as measured by -Dst, weakens, or its rate of growth slows, during the substorm expansion phase. Yet the expansion phase is known to inject energetic particles into the ring current, which should strengthen the storm. We propose to reconcile these apparently contradictory results by combining the virial theorem and a principle of energy partitioning between energy storage elements in a system with dissipation. As applied to the unloading description of the substorm expansion phase, the virial theorem states that -Dst is proportional to the sum of the total magnetic energy and twice the total kinetic energy in the magnetosphere including the tail. Thus if expansion phase involves converting magnetic energy stored in the tail into kinetic energy stored in the ring current, a drop in -Dst during expansion phase requires that less than half the drop in magnetic energy goes into the ring current, the rest going into the ionosphere. Indeed Weiss et al., have estimated that the energy dissipated in the ionosphere during expansion phase is twice that injected into the ring current. This conclusion is also consistent with the mentioned energy partitioning principle, which requires that more energy be dissipated than transferred between storage elements. While Iyemori and Rao's observations seem to contradict the hypothesis that storms consist at least in part of a sum of substorms, this mode of description might nonetheless be preserved by including the substorm's growthphase contribution. Then the change in storm strength measured from before the growth phase to after the expansion phase is positive, even though the expansion phase alone makes a negative contribution.

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Section: Must a Substorm Be A Sub-storm?mentioning

confidence: 99%

On storm weakening during substorm expansion phase

Siscoe

Petschek

1997

Ann Geophysicae

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“…The concept that a magnetic storm is a compilation of a series of substorms was proposed by Akasofu [1968]. However, Kamide [1992] showed that substorms are not a necessary condition for the occurrence of a magnetic storm. This contro versy initiated a new era of research on the storm-substorm relation, which was the subject of a recent workshop in Banff, Alberta, Canada.…”

Section: Page 234mentioning

confidence: 99%

Storm‐substorm relations workshop

Kan

2006

EoS Transactions

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Magnetic storms in the magnetosphere can cause damage to communication satellites and large‐scale power outages.The concept that a magnetic storm is a compilation of a series of substorms was proposed by Akasofu [1968]. However, Kamide [1992] showed that substorms are not a necessary condition for the occurrence of a magnetic storm. This controversy initiated a new era of research on the storm‐substorm relation, which was the subject of a recent workshop in Banff, Alberta, Canada. The main topics discussed during the meeting included a brief overview of what a substorm is, how quasiperiodic substorm events and steady magnetospheric convection (SMC) events without substorms contribute to storms, and how plasma flows enhanced by magnetic reconnection in the plasma sheet contribute to substorms and storms.

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“…Several studies have addressed the issue, without however achieving conclusive evidence (e.g., Kamide, 1992;Kamide and Allen, 1997;Daglis et al, 1998;Kamide et al, 1998a;Daglis, 2000;Daglis et al, 2000). Studies opposing the "Chapman-Akasofu paradigm" have claimed that substorm occurrence is incidental to the main phase of storms, and that ion transport into the ring current is accomplished solely by enhanced largescale convection electric fields, with no contribution from substorms at all.…”

Section: Ring Current Growth and Substorm Influencementioning

confidence: 99%

“…In other words, an individual substorm may cause only a "mini" ring current, but if substorms occur frequently enough, the injected ring current particles accumulate in the trapping region, forming the symmetrical ring current as a geomagnetic storm. It is not clear, however, whether the occurrence of substorms is a necessary condition for a magnetic storm, or merely coincidental (Kamide, 1992;Siscoe, 1997). Thus, a basic question remains unanswered involving whether a magnetic storm is a superposition of intense substorms, each of which constitutes an elementary storm.…”

Section: "Mini" Ring Currents Associated With Substormsmentioning

confidence: 99%

Space Storms and Space Weather Hazards

Daglis¹

2001

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Subject Terms Report Classification unclassified Classification of this page unclassified Classification of Abstract unclassified Limitation of Abstract UU Number of Pages 486REPORT DOCUMENTATION PAGE Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, -to review recent spacecraft measurements that have provided new insight into the dynamics and effects of space storms; -to review space weather hazards associated with space storms and pertinent to the operation of technological systems in space and on ground;-to discuss and assess methods of space weather forecasting, as well as national and international initiatives towards an efficient development of space climatology.Space weather, the invisible but nevertheless effective result of solar activity and solar-terrestrial coupling, has affected the operations of communication systems since the appearance of telegraph in the 19th century, though as an unknown trouble factor. Nowadays, the effects of space weather affect in various ways all communication modes, from cable to wireless to space-based systems. Moreover, space weather hazards include malfunction or even permanent damage of power distribution grids and of telecommunication, navigation and surveillance satellites, disturbances of over-the-horizon (OTH) radar, HF, VHF and UHF communications, surveying and navigation systems that use Global Positioning System (GPS) satellites, surveillance (optical and radar), and satellite tracking. Space weather influences on the Earth's weather and climate is still a developing topic. Little is known concerning the biological effects of space weather, especially regarding astronauts.This Institute could not be timelier. Space Weather, which has been defined as "conditions on the sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-and ground-based technological systems and can endanger human life", encompasses a broad range of phenomena impacting both space science and technology. The effects of Space Weather, while present throughout the solar cycle, gain particular prominence around the peak of the 11-year sunspot activity; the maximum of cycle 23 occurred in summer 2000.The fact that this ASI on Space Weather was held in Europe is particularly appropriate. European countries host a considerable repository of knowledge and world-class facilities in this field. Nevertheless, while Space Weather activities in c...

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Is Substorm Occurrence a Necessary Condition for a Magnetic Storm?

Abstract: It is shown that "having substorms" is not a necessary condition for a magnetic storm. The main phase of magnetic storms develops because of sustained, southward interplanetary magnetic field (IMF), not because of frequent occurrence of intense substorms.

Cited by 83 publications

References 22 publications

On storm weakening during substorm expansion phase

On storm weakening during substorm expansion phase

Storm‐substorm relations workshop

Space Storms and Space Weather Hazards

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