Coronal mass ejections: Some possibilities for prediction

Filippov, B. P.; Zagnetko, Alexander; Ajabshirizadeh, A.; Den, O. G.

doi:10.1134/s0038094606040083

Cited by 9 publications

(10 citation statements)

References 28 publications

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“…We note the agreement with the critical height calculated by Filippov et al (2006) and based on disk observations of filaments and magnetic fields.…”

Section: Distribution On Prominence Heightssupporting

confidence: 72%

On Critical Heights and Longitudinal Magnetic Field Strength in Prominences

Alexeeva¹,

Kim²

2013

Proc. IAU

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“…We note the agreement with the critical height calculated by Filippov et al (2006) and based on disk observations of filaments and magnetic fields.…”

Section: Distribution On Prominence Heightssupporting

confidence: 72%

On Critical Heights and Longitudinal Magnetic Field Strength in Prominences

Alexeeva¹,

Kim²

2013

Proc. IAU

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“…Filippov et al (2006) found that prominences are stable until they reach a critical height given by the vertical scale height of the magnetic field in the vicinity of the prominence. Figure 12c shows a scatter plot between the critical height (H c ) and the observed height (H p ) taken from Filippov and Den (2001) and Filippov et al (2006). Clearly, prominences with H p ≥ H c erupted, while those with H p < H c remained stable.…”

Section: Starting Height Of Cmesmentioning

confidence: 99%

Properties of Ground Level Enhancement Events and the Associated Solar Eruptions During Solar Cycle 23

et al. 2012

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Solar cycle 23 witnessed the most complete set of observations of coronal mass ejections (CMEs) associated with the Ground Level Enhancement (GLE) events. We present an overview of the observed properties of the GLEs and those of the two associated phenomena, viz., flares and CMEs, both being potential sources of particle acceleration. Although we do not find a striking correlation between the GLE intensity and the parameters of flares and CMEs, the solar eruptions are very intense involving X-class flares and extreme CME speeds (average ∼2000 km/s). An M7.1 flare and a 1200 km/s CME are the weakest events in the list of 16 GLE events. Most (80 %) of the CMEs are full halos with the three nonhalos having widths in the range 167 to 212 degrees. The active regions in which the GLE events originate are generally large: 1290 msh (median 1010 msh) compared to 934 msh (median: 790 msh) for SEP-producing active regions. For accurate estimation of the CME height at the time of metric type II onset and GLE particle release, we estimated the initial acceleration of the CMEs using flare and CME observations. The initial acceleration of GLE-associated CMEs is much larger (by a factor of 2) than that of ordinary CMEs (2.3 km/s 2 vs. 1 km/s 2 ). We confirmed the initial acceleration for two events for which CME measurements are available in the inner corona. The GLE particle release is delayed with respect to the onset of all electromagnetic signatures of the eruptions: type II bursts, low frequency type III bursts, soft X-ray flares and CMEs. The presence of metric type II radio bursts some 17 min (median: 16 min; range: 3 to 48 min) before the GLE onset indicates shock formation well before the particle release. The release of GLE particles occurs when the CMEs reach an average height of ∼3.09 R s (median: 3.18 R s ; range: 1.71 to 4.01 R s ) for well-connected events (source longitude in the range W20-W90). events, the average CME height at GLE particle release is ∼66 % larger (mean: 5.18 R s ; median: 4.61 R s ; range: 2.75-8.49 R s ). The longitudinal dependence is consistent with shock accelerations because the shocks from poorly connected events need to expand more to cross the field lines connecting to an Earth observer. On the other hand, the CME height at metric type II burst onset has no longitudinal dependence because electromagnetic signals do not require magnetic connectivity to the observer. For several events, the GLE particle release is very close to the time of first appearance of the CME in the coronagraphic field of view, so we independently confirmed the CME height at particle release. The CME height at metric type II burst onset is in the narrow range 1.29 to 1.8 R s , with mean and median values of 1.53 and 1.47 R s . The CME heights at metric type II burst onset and GLE particle release correspond to the minimum and maximum in the Alfvén speed profile. The increase in CME speed between these two heights suggests an increase in Alfvénic Mach number from 2 to 3. The CME heights at GLE particle r...

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“…Thus, if you have previously met supernova remnants, Venn diagrams, and the Small Magellanic Cloud, you cannot be led too far astray by Venn diagrams of SNRs in the SMC (Filippov et al 2006). On the other hand, when Abad and Viera (2005) describe star streams identified by using Herschel's method, without citing Herschel, you might be led to suppose the method means extreme exploitation of sibling labor.…”

Section: Familiar Physics Expected Effects and Wonderful Widgetsmentioning

confidence: 95%

“…Prominences are thought to be the best tracer of the helical flux ropes that drive a CME (Filippov et al 2006). A combination of SoHO and Ulysses data allowed to track the formation of a current sheet in the aftermath of a CME down from the corona all the way out to interplanetary distances (Bemporad et al 2006), out to 5.4 AU (Wang et al 2005a) and 20 AU (Liu et al 2006g).…”

Section: Propagation Of Cmesmentioning

confidence: 97%

Astrophysics in 2006

2007

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The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the universe) and others of which there are always many, like meteors and molecules, black holes and binaries.Comment: 244 pages, no figure

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Coronal mass ejections: Some possibilities for prediction

Cited by 9 publications

References 28 publications

On Critical Heights and Longitudinal Magnetic Field Strength in Prominences

On Critical Heights and Longitudinal Magnetic Field Strength in Prominences

Properties of Ground Level Enhancement Events and the Associated Solar Eruptions During Solar Cycle 23

Astrophysics in 2006

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