Interplanetary coronal mass ejections in the near‐Earth solar wind during 1996–2002

Abstract

[1] We summarize the occurrence of interplanetary coronal mass ejections (ICMEs) in the near-Earth solar wind during 1996-2002, corresponding to the increasing and maximum phases of solar cycle 23. In particular, we give a detailed list of such events. This list, based on in situ observations, is not confined to subsets of ICMEs, such as ''magnetic clouds'' or those preceded by ''halo'' coronal mass injections (CMEs) observed by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph, and provides an overview of 214 ICMEs in the near-Earth solar wind during this period. The ICME rate increases by about an order of magnitude from solar minimum to solar maximum (when the rate is $3 ICMEs per solar rotation period). The rate also shows a temporary reduction during 1999 and another brief, deeper reduction in late 2000 to early 2001, which only approximately track variations in the solar 10-cm flux. In addition, there are occasional periods of several rotations duration when the ICME rate is enhanced in association with high solar activity levels. We find an indication of a periodic variation in the ICME rate, with a prominent period of $165 days similar to that previously reported in various solar phenomena. It is found that the fraction of ICMEs that are magnetic clouds has a solar cycle variation, the fraction being larger near solar minimum. For the subset of events that we could associate with a CME at the Sun the transit speeds from the Sun to the Earth were highest after solar maximum.

Characteristics of the interplanetary coronal mass ejections in the heliosphere between 0.3 and 5.4 AU

“…ICMEs with speeds high enough relative to the ambient solar wind may generate shocks ahead of them [Sheeley et al, 1985;Bothmer and Schwenn, 1996]. However, individual signatures may not be detected in all ICMEs [Cane and Richardson, 2003]. Even if several signatures are present in an ICME, they are not necessarily coincident.…”

“…Even if several signatures are present in an ICME, they are not necessarily coincident. Some signatures have been reported relatively infrequently, while other signatures, such as proton temperature depressions, are generally present [Richardson and Cane, 1995;Cane and Richardson, 2003].…”

Propagation and Evolution of ICMES in the Solar Wind

“…We refer in this paper to the list developed by Cane and Richardson [2003] (hereafter referred to as C&R) using data from 1996 through 2002 which covered the period from solar minimum to solar maximum. The starting point for this list is the criterion that the observed temperature, , be less than 0.5 of the temperature expected for the observed solar wind speed, " !…”

Space Weather: Physics, Effects and Predictability

“…Several authors have used the plane-of-sky speed for forecasting (Gopalswami et al 2001;Cane and Richardson 2003;Michalek et al 2003); the plane-of-sky speed is oriented perpendicular to the Sun-Earth line. Schwenn et al (2005) have developed an empirical relationship between the CMEs travel time to 1 AU and its expansion speed in the SOHO coronagraph's field of view.…”