An overview of the early November 1993 geomagnetic storm

Abstract

Abstract. This paper describes the development of a major space storm during November 2-11, 1993. We discuss the history of the contributing high-speed stream, the powerful combination of solar wind transients and a corotating interaction region which initiated the storm, the high-speed flow which prolonged the storm and the near-Earth manifestations of the storm. The 8-day storm period was unusually long; the result of a high-speed stream (maximum speed 800 km/s) emanating from a distended coronal hole. Storm onset was accompanied by a compression of the entire dayside magnetopause to within geosynchronous Earth orbit (GEO). For nearly 12 hours the near-Earth environment was in a state of tumult. A super-dense plasma sheet was observed at GEO, and severe spacecraft charging was reported. The effects of electrons precipitating into the atmosphere penetrated into the stratosphere. Subauroral electron content varied by 100% and F layer heights oscillated by 200 km. Equatorial plasma irregularities extended in plumes to heights of 1400 km. Later, energetic particle fluxes at GEO recovered and rose by more than an order of magnitude. A satellite anomaly was reported during the interval of high energetic electron flux. Model results indicate an upper atmospheric temperature increase of 200øK within 24 hours of storm onset. Joule heating for the first 24 hours of the storm was more than 3 times that for typical active geomagnetic conditions. We estimate that total global ionospheric heating for the full storm interval was-190 PJ, with 30% of that generated within 24 hours of storm onset.

A study of Pc-5 ULF oscillations

“…Toroidal mode power is distributed fairly equally between the dawn and dusk flanks of the magnetosphere inside L = 8, with greater probability of occurrence at higher L-values. The former result differs from AMPTE CCE and AMPTE IRM satellite studies at higher L-values at solar minimum (Anderson et al, 1990;Lessard et al, 1999;Takahashi et al, 2002), but is consistent with a recent analysis of a six month interval of GOES 6 geosynchronous data in 1993, a period characterized by 27-day recurring high speed solar wind streams characteristic of the declining phase of the solar cycle (Knipp et al, 1998). The occurence of Pc-5 oscillations has been correlated with high speed solar wind periods O'Brien et al, 2001), providing some support for the Kelvin-Helmholtz theory of toroidal mode FLR excitation.…”

Energetics of magnetic storms driven by corotating interaction regions: A study of geoeffectiveness

“…They did not estimate the energy lost to plasmoids streaming down the magnetotail. Knipp et al [1998] analyzed the November 1993 storm, which was a hybrid event where a high-speed stream followed a CME. They found that high-speed streams could be enormously geoeffective, and for this extreme event the ionospheric heating was ∼190 × 10 15 J, with 30% of that generated within 24 hours of storm onset.…”

Ionosphere-thermosphere (IT) response to solar wind forcing during magnetic storms

“…Over many years of research into the effects of solar wind forcing on the ionosphere-thermosphere (IT) system, it has been generally assumed that energy enters and dissipates in the auroral zones and ring current (Akasofu 1981;Weiss et al 1992; Knipp et al 1998;Li et al 2012, and references therein). This assumption is based on the effect of particle precipitation which gives rise to intense auroral emissions and high conductivity in the auroral zone (Evans et al 1977;Vondrak & Robinson 1985;Fuller-Rowell & Evans 1987;Coumans et al 2004, and many others).…”