Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Gopalswamy, N.; Tsurutani, B. T.; Yan, Yihua

doi:10.1186/s40645-015-0043-8

Cited by 50 publications

(68 citation statements)

References 341 publications

(515 reference statements)

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“…The low shock formation height also implies that the associated CMEs accelerate impulsively (initial acceleration is ~2 km s -2 ) to reach supermagnetosonic speeds. On the other hand, in FE SEP events, particles are not accelerated to high energies, consistent with shock formation at large distances from the Sun and the soft spectrum (Gopalswamy et al 2015a). The regular SEP events show intermediate behavior in shock formation height, initial acceleration, and spectral hardness.…”

Section: Implications: Hierarchical Relationshipmentioning

confidence: 72%

“…Some of these are likely to be due to CMEs behaving similar to those in FE SEP events in that they typically have positive acceleration in the coronagraph FOV resulting in shock formation at larger distances. Several such events were also reported in Gopalswamy et al (2015a). It is also possible that some are indeed FE SEP events, but were not identified as such.…”

Section: Statistical Comparisonsmentioning

confidence: 99%

“…For example, the shock transit time from the Sun to 1 au was ~18.5 hours, similar to the two 2003 Halloween events on October 28 and 29 and to 13 other fast-transit events since the Carrington event in 1859 (Gopalswamy et al 2005a;Cliver et al 1990a,b). Based on the measured magnetic field and plasma properties, it was estimated that the CME would have caused a geomagnetic storm comparable to that of the 1859 Carrington storm if it were Earthdirected (Baker et al 2013;Liu et al 2014;Gopalswamy et al 2014a;2015a). The solar energetic particle (SEP) event associated with the shock was so intense that the shock properties were significantly affected by the nonthermal particles ).…”

Section: Introductionmentioning

confidence: 99%

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The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?

Gopalswamy

Yashiro

Thakur

et al. 2016

ApJ

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The backside coronal mass ejection (CME) of 2012 July 23 had a short Sun to Earth shock transit time (18.5 hours). The associated solar energetic particle (SEP) event had a >10 MeV proton flux peaking at ~5000 pfu, and the energetic storm particle (ESP) event was an order of magnitude larger, making it the most intense event in the space era at these energies. By a detailed analysis of the CME, shock, and SEP characteristics, we find that the July 23 event is consistent with a high-energy SEP event (accelerating particles to GeV energies). The time of maximum and fluence spectra in the range 10-100 MeV were very hard, similar to those of ground level enhancement (GLE) events. We found a hierarchical relationship between the CME initial speeds and the fluence spectral indices: CMEs with low initial speeds had SEP events with the softest spectra, while those with highest initial speeds had SEP events with the hardest spectra. CMEs attaining intermediate speeds result in moderately hard spectra. The July 23 event was in the group of hard-spectrum events. During the July 23 event, the shock speed (>2000 km s -1 ), the initial acceleration (~1.70 km s -2 ), and the shock formation height (~1.5 solar radii) were all typical of GLE events. The associated type II burst had emission components from metric to kilometric wavelengths suggesting a strong shock. These observation confirm that the 2012 July 23 event is likely to be an extreme event in terms of the energetic particles it accelerated.

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Section: Implications: Hierarchical Relationshipmentioning

confidence: 72%

Section: Statistical Comparisonsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?

Gopalswamy

Yashiro

Thakur

et al. 2016

ApJ

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“…Halo CMEs constitute only approximate 3% of all CMEs and represent an energy population because most of the CMEs that produce major geomagnetic storms are Halo [14]. There only 11 CMEs that caused major storms during cycle 24 until the end of period 2014 [15]. CMEs number shows a double peak and similar to seen in sunspot number [16].…”

Section: Introductionmentioning

confidence: 99%

Effect of Coronal Mass Ejection on Earth’s Magnetic Field during Ascending Phase of Solar Cycles 23-24

Nigam¹,

Singh²,

Chamadia³

et al. 2017

IJAA

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We have studied the width and speed of coronal mass ejections (CMEs) and geomagnetic disturbance storm time (Dst) Index during ascending phase of solar cycles 23 and 24. We have classified total CMEs according to angular width and speed for the ascending period 1996-2002 and 2008-2014. We have found that the width of 62% CMEs is narrow, and 3% are Halo for the solar cycle 23 and 73% CMEs are narrow, and 2% CMEs are Halo for the solar cycle 24. The speed distribution of 65% CMEs has speed ≤ 500 km/sec and 4% CMEs has speed > 1000 km/sec for solar cycle 23 and 84% CMEs has speed ≤ 500 km/sec and 1% CMEs has speed > 1000 km/sec in cycle 24. The relationship between width and speed is more pronounced for fast ejecta (>1000 km/sec.), while slower ejecta shows more astronomically immense scatter. We have reported that the correlation between Dst and CMEs for ascending phase of solar cycle 24 is less than as compare to ascending phase of solar cycle 23.

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“…Detailed reviews of the scientific achievements relevant to each TG can be found in Seppälä et al (2014) for TG1, Laštovička et al (2014) for TG2, Gopalswamy et al (2015) for TG3, Oberheide et al (2015) for TG4, and Fox and Kozyra (2015) for E-science.…”

Section: Scientific Achievements Of Cawses IImentioning

confidence: 99%

Advancing the understanding of the Sun–Earth interaction—the Climate and Weather of the Sun–Earth System (CAWSES) II program

Tsuda

Shepherd

Gopalswamy

2015

Prog. in Earth and Planet. Sci.

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The Scientific Committee on Solar-Terrestrial Physics (SCOSTEP) of the International Council for Science (ICSU) implemented an international collaborative program called Climate and Weather of the Sun-Earth System (CAWSES), which was active from 2004 to 2008; this was followed by the CAWSES II program during the period of 2009-2013. The CAWSES program was aimed at improving the understanding of the coupled solar-terrestrial system, with special emphasis placed on the short-term (weather) and long-term (climate) variability of solar activities and their effects on and responses of Geospace and Earth's environment. Following the successful implementation of CAWSES, the CAWSES II program pursued four fundamental questions addressing the way in which the coupled Sun-Earth system operates over time scales ranging from minutes to millennia, namely, (1) What are the solar influences on the Earth' s climate? (2) How will Geospace respond to an altered climate? (3) How does short-term solar variability affect the Geospace environment? and (4) What is the Geospace response to variable inputs from the lower atmosphere? In addition to these four major tasks, the SCOSTEP and CAWSES promoted E-science and informatics activities including the creation of scientific databases and their effective utilization in solar-terrestrial physics research. Capacity building activities were also enhanced during CAWSES II, and this represented an important contribution of SCOSTEP to the world's solar-terrestrial physics community. This introductory paper provides an overview of CAWSES II activities and serves as a preface to the dedicated review papers summarizing the achievements of the program's four task groups (TGs) and the E-science component.

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Short-term variability of the Sun-Earth system: an overview of progress made during the CAWSES-II period

Cited by 50 publications

References 341 publications

The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?

The 2012 July 23 Backside Eruption: An Extreme Energetic Particle Event?

Effect of Coronal Mass Ejection on Earth’s Magnetic Field during Ascending Phase of Solar Cycles 23-24

Advancing the understanding of the Sun–Earth interaction—the Climate and Weather of the Sun–Earth System (CAWSES) II program

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