An Early Diagnostics of the Geoeffectiveness of Solar Eruptions from Photospheric Magnetic Flux Observations: The Transition from SOHO to SDO

Chertok, I. M.; Grechnev, V. V.; Аbunin, А. А.

doi:10.1007/978-94-024-1570-4_35

Cited by 2 publications

(2 citation statements)

References 38 publications

(35 reference statements)

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“…We compute the total magnetic flux underlying the PEA area (9.80×10 19 cm 2 ) that has an average unsigned field strength <B> = 258.5 G as 2.53×10 22 Mx. Chertok et al (2017) obtained a similar value for the total erupted flux (2.34×10 22 Mx) although their criteria include the dimming flux, which is generally smaller than the arcade flux. According to the PEA technique developed by Gopalswamy et al (2017a), the reconnected flux is half the flux under the PEA: 1.27×10 22 Mx.…”

Section: Reconnected Flux and 1-au Magnetic Field Strengthmentioning

confidence: 83%

Sun-to-earth propagation of the 2015 June 21 coronal mass ejection revealed by optical, EUV, and radio observations

Gopalswamy

Mäkelä

Akiyama

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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We investigate the propagation of the 2015 June 21 CME-driven shock as revealed by the type II bursts at metric and longer wavelengths and coronagraph observations. The CME was associated with the second largest geomagnetic storm of solar cycle 24 and a large solar energetic particle (SEP) event. The eruption consisted of two M-class flares, with the first one being confined, with no metric or interplanetary radio bursts. However, there was intense microwave burst, indicating accelerated particles injected toward the Sun. The second flare was eruptive that resulted in a halo CME. The CME was deflected primarily by an equatorial coronal hole that resulted in the modification of the intensity profile of the associated SEP event and the duration of the CME at Earth. The interplanetary type II burst was particularly intense and was visible from the corona all the way to the vicinity of the Wind spacecraft with fundamental-harmonic structure. We computed the shock speed using the type II drift rates at various heliocentric distances and obtained information on the evolution of the shock that matched coronagraph observations near the Sun and in-situ observations near Earth. The depth of the geomagnetic storm is consistent with the 1-AU speed of the CME and the magnitude of the southward component.One of the controversies in this event is the low speed of the CME (~330 km s -1 ) in the outer corona (~26 solar radii) assumed by Piersanti et al. (2017), based on measurements provided by the CORIMP automatic CME catalog. With such low speed, these authors estimated the shock arrival at Earth on June 25, while the shock arrived on June 22, about 39.5 hours after the eruption. In fact, the shock and interplanetary (IP) CME (ICME) speeds were much higher at 1 AU (>700 km s -1 ). This is one of the motivations to clarify the CME kinematics near the Sun because we know that CMEs that survive into the IP medium to reach Earth are generally fast and wide (Gopalswamy et al. 2010a). We show that the shock speed is consistently high throughout the inner heliosphere and the deceleration is typical of most CMEs reported in the literature. We also use multiple methods to infer the true speed of the shock from white-light and radio data. In particular, we use IP type II radio burst data to derive the shock speed in the inner heliosphere. The CME and the shock are tightly coupled, so it is not possible to have a 330 km s -1 CME driving a >1000 km s -1 shock.The solar source of the CME has not received much attention in the literature (Liu et al. 2015;Piersanti et al. 2017). Soft-X-ray observations show two M-class flares in quick succession from the same active region. We examine the spatial distribution of the flare emission to show that it is different during the two flares: the first flare (X-ray class M2.0) was confined (no mass motion), while the second one (M2.6) was eruptive and hence associated with the CME in question.Another motivation stems from the confusion regarding the nature and extent of the IP counterpart of the 2015 Ju...

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Section: Reconnected Flux and 1-au Magnetic Field Strengthmentioning

confidence: 83%

Sun-to-earth propagation of the 2015 June 21 coronal mass ejection revealed by optical, EUV, and radio observations

Gopalswamy

Mäkelä

Akiyama

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Within this region, the flux is calculated for all pixels with absolute fields above 50 G. Due to the limitations related to the projection effects involved in the magnetic flux determination, we only show values corresponding to the dates when the AR was on central meridian ± 4 days. The resulting MDI flux curves were divided by a cross-calibration factor of 1.40 to make them comparable to the HMI results, see Liu et al (2012b); Chertok et al (2019).…”

Section: Photospheric Propertiesmentioning

confidence: 99%

Analysis of a long-duration AR throughout five solar rotations: Magnetic properties and ejective events

Iglesias

Cremades

Merenda

et al. 2020

Advances in Space Research

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Coronal mass ejections (CMEs), which are among the most magnificent solar eruptions, are a major driver of space weather and can thus affect diverse human technologies. Different processes have been proposed to explain the initiation and release of CMEs from solar active regions (ARs), without reaching consensus on which is the predominant scenario, and thus rendering impossible to accurately predict when a CME is going to erupt from a given AR. To investigate AR magnetic properties that favor CMEs production, we employ multi-spacecraft data to analyze a long duration AR (NOAA 11089, 11100, 11106, 11112 and 11121) throughout its complete lifetime, spanning five Carrington rotations from July to November 2010. We use data from the Solar Dynamics Observatory to study the evolution of the AR magnetic properties during the five near-side passages, and a proxy to follow the magnetic flux changes when no magnetograms are available, i.e. during farside transits. The ejectivity is studied by characterizing the angular widths, speeds and masses of 108 CMEs that we associated to the AR, when examining a 124-day period. Such an ejectivity tracking was possible thanks to the mulit-viewpoint images provided by the Solar-Terrestrial Relations Observatory and Solar and Heliospheric Observatory in a quasi-quadrature configuration. We also inspected the X-ray flares registered by the GOES satellite and found 162 to be associated to the AR under study. Given the substantial number of ejections studied, we use a statistical approach instead of a single-event analysis. We found three well defined periods of very high CMEs activity and two periods with no mass ejections that are preceded or accompanied by characteristic changes in the AR magnetic flux, free magnetic energy and/or presence of electric currents. Our large sample of CMEs and long term study of a single AR, provide further evidence relating AR magnetic activity to CME and Flare production.

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An Early Diagnostics of the Geoeffectiveness of Solar Eruptions from Photospheric Magnetic Flux Observations: The Transition from SOHO to SDO

Cited by 2 publications

References 38 publications

Sun-to-earth propagation of the 2015 June 21 coronal mass ejection revealed by optical, EUV, and radio observations

Sun-to-earth propagation of the 2015 June 21 coronal mass ejection revealed by optical, EUV, and radio observations

Analysis of a long-duration AR throughout five solar rotations: Magnetic properties and ejective events

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