Continuous tracking of coronal outflows: Two kinds of coronal mass ejections

Recent advances in wide-angle imaging by the Solar Mass Ejection Imager (SMEI) on board the Coriolis spacecraft and more recently by the Heliospheric Imagers (HI) aboard NASA's Solar TErrestrial RElations Observatory (STEREO), have enabled solar wind transients to be imaged and tracked from the Sun to 1 AU and beyond. In this paper we consider two of the techniques that have been used to determine the propagation characteristics of solar wind transients based on single-spacecraft observations, in particular propagation direction and radial speed. These techniques usually assume that the observing spacecraft remains stationary for the duration of observation of the solar wind transient. We determine the inaccuracy introduced by this assumption for the two STEREO spacecraft and find that it can be significant, and it can lead to an overestimation of the transient velocity as seen from STEREO-A and an underestimation as seen by STEREO-B. This has implications for the prediction or solar wind transients at 1 AU and hence is important for the study of space weather.

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“…Harrison et al, 2012). For more information on J-maps see Sheeley and Walters (1999) and Davies et al (2009).…”

Section: J-maps and Time-elongation Profile Fittingmentioning

confidence: 99%

Assessing the Effect of Spacecraft Motion on Single-Spacecraft Solar Wind Tracking Techniques

2014

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“…We empirically know, however, that CMEs associated with flares in active regions are also common (e.g., Munro et al [1979]). Based on the acceleration profiles and morphologies, there seem to be two types of CMEs [Sheeley et al, 1999], and it is likely that those which start fast and then decelerate correspond to flares more directly (cf., MacQueen and Fisher [1983]). Fast CMEs may produce interplanetary shocks that are considered to be responsible for major solar energetic particle (SEP) events observed near Earth IReames, 1999].…”

Section: Introductionmentioning

confidence: 99%

Recurrent flare/CME events from an emerging flux region

Nitta¹,

Hudson²

2001

Geophysical Research Letters

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were not long-decay events (LDEs) in terms of soft X-ray light curves and morphologies, although, in the impulsive phase, they produced ejections in soft X-rays that are characteristic of CMEs. We do not detect global changes in EUV and X-ray full-disk images prior to these flares. We suggest that emerging magnetic flux in the core of an active region may be responsible for the occurrence of such repeated fiare/CME events.

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“…Their distribution of CME speeds was very similar to that found by Hundhausen et al, (1994), with a peak near 300 km/s, and a long tail extending above 1500 km/s. However, Sheeley et al, (1999) used a differencing method to study the motion of CMEs, and, using a more limited sample, claimed that CMEs fell into two different types (see also MacQueen and Fisher, (1983), for a similar conclusion based on Mauna Loa observations). These were: gradual CMEs with a speed in the range 400 -600 km/s and apparently associated with prominence eruptions and secondly, fast CMEs with speeds in excess of 750 km/s, and associated with flares.…”

Section: Mass Velocity Acceleration and Energymentioning

confidence: 99%

“…This may seem to be an easier problem, but really it is not. One would expect fast CMEs to undergo prompt deceleration, yet that does not happen, at least inside 30 R s (Sheeley et al, 1999). So does this mean that CMEs are strongly driven to beyond 30 R s in order to overcome drag forces?…”

Section: Where Cme Research Standsmentioning

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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Continuous tracking of coronal outflows: Two kinds of coronal mass ejections

Cited by 540 publications

References 53 publications

Assessing the Effect of Spacecraft Motion on Single-Spacecraft Solar Wind Tracking Techniques

Assessing the Effect of Spacecraft Motion on Single-Spacecraft Solar Wind Tracking Techniques

Recurrent flare/CME events from an emerging flux region

Space Storms and Space Weather Hazards

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