The Source Regions of Solar Energetic Particles Detected by Widely Separated Spacecraft

Park, Jinhye; Innes, D. E.; Bučík, R.; Moon, Yong‐Jae

doi:10.1088/0004-637x/779/2/184

Cited by 57 publications

(67 citation statements)

References 28 publications

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“…The dashed line is a linear least squares fit to the data, and is the correlation coefficient. Images reproduced with permission from [left] Vainio and Khan (2004) and [right] from Park et al (2013), copyright by AAS. Vainio and Khan (2004) have considered particle acceleration at a refracting coronal shock, which refers to a shock front that becomes tilted towards the solar surface due to the increase of the fast-mode speed with height in the low corona (see Section 6.1).…”

Section: Acceleration Of Solar Energetic Particles (Seps)mentioning

confidence: 99%

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Large-scale Globally Propagating Coronal Waves

Warmuth

2015

Living Rev. Sol. Phys.

163

140

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Large-scale, globally propagating wave-like disturbances have been observed in the solar chromosphere and by inference in the corona since the 1960s. However, detailed analysis of these phenomena has only been conducted since the late 1990s. This was prompted by the availability of high-cadence coronal imaging data from numerous spaced-based instruments, which routinely show spectacular globally propagating bright fronts. Coronal waves, as these perturbations are usually referred to, have now been observed in a wide range of spectral channels, yielding a wealth of information. Many findings have supported the "classical" interpretation of the disturbances: fast-mode MHD waves or shocks that are propagating in the solar corona. However, observations that seemed inconsistent with this picture have stimulated the development of alternative models in which "pseudo waves" are generated by magnetic reconfiguration in the framework of an expanding coronal mass ejection. This has resulted in a vigorous debate on the physical nature of these disturbances. This review focuses on demonstrating how the numerous observational findings of the last one and a half decades can be used to constrain our models of large-scale coronal waves, and how a coherent physical understanding of these disturbances is finally emerging. Article RevisionsLiving Reviews supports two ways of keeping its articles up-to-date:Fast-track revision. A fast-track revision provides the author with the opportunity to add short notices of current research results, trends and developments, or important publications to the article. A fast-track revision is refereed by the responsible subject editor. If an article has undergone a fast-track revision, a summary of changes will be listed here.Major update. A major update will include substantial changes and additions and is subject to full external refereeing. It is published with a new publication number.For detailed documentation of an article's evolution, please refer to the history document of the article's online version at http://dx

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Section: Acceleration Of Solar Energetic Particles (Seps)mentioning

confidence: 99%

“…To take an example, Park et al (2013) have used STEREO and SDO data to find a good correlation between EUV wave arrival times at the connecting magnetic footpoints and the SEP injection times in 12 events (see right panel in Figure 50). …”

Section: Acceleration Of Solar Energetic Particles (Seps)mentioning

confidence: 99%

Large-scale Globally Propagating Coronal Waves

Warmuth

2015

Living Rev. Sol. Phys.

163

140

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“…A window 90 minutes either side of the start time of the global wave was used to look for associated events in the NOAA/SWPC list. This choice of time window was motivated by the fact that type II radio bursts can be seen up to 15 minutes before or after the first instance of an EUV wave observation (Park et al, 2013;Warmuth, 2010;Miteva et al, 2014); the larger time window used here was chosen to account for any anomalous events. For each candidate radio burst associated with a global wave, the SWPC list provides an associated start time, an end time, the observatory used to make the observation, the frequency range of the burst and the estimated drift speed.…”

Section: Identification and Characterisation Of Type II Radio Burstsmentioning

confidence: 99%

“…Although previous work by Park et al (2013Park et al ( , 2015 compared wave propagation to a potential field source surface extrapolation of the solar corona to compare the time at which the wave encountered a connected field line with the inferred SEP release times, this approach is rarely taken. However, the results described here suggest that a full understanding of the ability of a global wave to accelerate SEPs must combine the propagation of the wave with a full understanding of the coronal and heliospheric magnetic field.…”

Section: Relationship With Solar Energetic Particle Eventsmentioning

confidence: 99%

A Statistical Analysis of the Solar Phenomena Associated with Global EUV Waves

et al. 2017

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Solar eruptions are the most spectacular events in our solar system and are associated with many different signatures of energy release including solar flares, coronal mass ejections, global waves, radio emission and accelerated particles. Here, we apply the Coronal Pulse Identification and Tracking Algorithm (CorPITA) to the high-cadence synoptic data provided by the Solar Dynamics Observatory (SDO) to identify and track global waves observed by SDO. 164 of the 362 solar flare events studied (45%) were found to have associated global waves with no waves found for the remaining 198 (55%). A clear linear relationship was found between the median initial velocity and the acceleration of the waves, with faster waves exhibiting a stronger deceleration (consistent with previous results). No clear relationship was found between global waves and type II radio bursts, electrons or protons detected in situ near Earth. While no relationship was found between the wave properties and the associated flare size (with waves produced by flares from B to X-class), more than a quarter of the active regions studied were found to produce more than one wave event. These results suggest that the presence of a global wave in a solar eruption is most likely determined by the structure and connectivity of the erupting active region and the surrounding quiet solar corona rather than by the amount of free energy available within the active region.

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“…Because they are very confined regions, these sources are expected to lead to narrow longitudinal spreads inside the inner A&A 567, A27 (2014) events (Krucker et al 1999;Rouillard et al 2012;Park et al 2013). These EIT waves are seen as coronal disturbances in EUV images, that were first observed with the EIT instrument onboard SOHO (Moses et al 1997; Thompson et al 1998).…”

Section: Introductionmentioning

confidence: 98%

Statistical survey of widely spread out solar electron events observed with STEREO and ACE with special attention to anisotropies

Dresing

Gómez-Herrero

Heber

et al. 2014

A&A

133

144

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Context. In February 2011, the two STEREO spacecrafts reached a separation of 180 degrees in longitude, offering a complete view of the Sun for the first time ever. When the full Sun surface is visible, source active regions of solar energetic particle (SEP) events can be identified unambiguously. STEREO, in combination with near-Earth observatories such as ACE or SOHO, provides three well separated viewpoints, which build an unprecedented platform from which to investigate the longitudinal variations of SEP events. Aims. We show an ensemble of SEP events that were observed between 2009 and mid-2013 by at least two spacecrafts and show a remarkably wide particle spread in longitude (wide-spread events). The main selection criterion for these events was a longitudinal separation of at least 80 degrees between active region and spacecraft magnetic footpoint for the widest separated spacecraft. We investigate the events statistically in terms of peak intensities, onset delays, and rise times, and determine the spread of the longitudinal events, which is the range filled by SEPs during the events. Energetic electron anisotropies are investigated to distinguish the source and transport mechanisms that lead to the observed wide particle spreads. Methods. According to the anisotropy distributions, we divided the events into three classes depending on different source and transport scenarios. One potential mechanism for wide-spread events is efficient perpendicular transport in the interplanetary medium that competes with another scenario, which is a wide particle spread that occurs close to the Sun. In the latter case, the observations at 1 AU during the early phase of the events are expected to show significant anisotropies because of the wide injection range at the Sun and particle-focusing during the outward propagation, while in the first case only low anisotropies are anticipated. Results. We find events for both of these scenarios in our sample that match the expected observations and even different events that do not agree with the scenarios. We conclude that probably both an extended source region at the Sun and perpendicular transport in the interplanetary medium are involved for most of these wide-spread events.

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The Source Regions of Solar Energetic Particles Detected by Widely Separated Spacecraft

Cited by 57 publications

References 28 publications

Large-scale Globally Propagating Coronal Waves

Large-scale Globally Propagating Coronal Waves

A Statistical Analysis of the Solar Phenomena Associated with Global EUV Waves

Statistical survey of widely spread out solar electron events observed with STEREO and ACE with special attention to anisotropies

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