An Interpretation of the Possible Mechanisms of Two Ground-Level Enhancement Events

Firoz, K. A.; Gan, Weiqun; Moon, Yong‐Jae; Li, C.

doi:10.1088/0004-637x/758/2/119

Cited by 24 publications

(14 citation statements)

References 51 publications

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“…Observationally, for individual GLE event, it is necessary to evaluate proton energy E p from its estimated time of travel to the Earth along the IMF path length under the assumption of scatter-free propagation. Firoz et al (2011a,b) proposed empirical method to on the determination of possible relativistic energies of GLE69 and GLE70 that we testified recently for the interpretation of possible acceleration mechanisms for the same two events (Firoz et al 2012). Deducing from observations the time lag ∆t of GLE onset with respect to the related flare or CME, we can obtain the velocity of GLE protons v p = L/(∆t + 8.3min).…”

Section: Energy Of Gle Protonsmentioning

confidence: 95%

Electron and Proton Acceleration During the First Ground Level Enhancement Event of Solar Cycle 24

Firoz

Sun

et al. 2013

ApJ

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High-energy particles were recorded by the near-Earth spacecraft and groundbased neutron monitors (NMs) on 2012 May 17. This event was the first Ground Level Enhancement (GLE) of the solar cycle 24. In present study, we try to identify the acceleration source(s) of solar energetic particles (SEPs) by combining in-situ particle measurements from W IND/3DP, GOES 13, and solar cosmic rays (SCRs) registered by several NMs, as well as the remote-sensing solar observations from SDO/AIA, SOHO/LASCO, and RHESSI. We derive the interplanetary magnetic field (IMF) path length (1.25 ± 0.05 AU) and solar particle release (SPR) time (01:29 ± 00:01 UT) of the first arriving electrons by using their velocity dispersion and taking into account the contamination effects. It is found that the electron impulsive injection phase, indicated by the dramatic change of spectral index, is consistent with the flare non-thermal emission and type III radio bursts. Based on the potential field source surface (PFSS) concept, a modeling of the open-field lines rooted in the active region (AR) has been performed to provide escaping channels for flare-accelerated electrons. Meanwhile, relativistic protons are found to be released ∼10 min later than the electrons, assuming their scatter-free travel along the same IMF path length. Combining multi-wavelength imaging data on the prominence eruption and coronal mass ejection (CME), we obtain some evidence of that GLE protons, with estimated kinetic energy of ∼1.12 GeV, are probably accelerated by the CME-driven shock when it travels to ∼3.07 solar radii. The time-of-maximum (TOM) spectrum of protons is typical for the shock wave acceleration.

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Section: Energy Of Gle Protonsmentioning

confidence: 95%

Electron and Proton Acceleration During the First Ground Level Enhancement Event of Solar Cycle 24

Firoz

Sun

et al. 2013

ApJ

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“…As one example, interplanetary shock acceleration of energetic charged particles (called "solar cosmic rays") is due to an ICME ram energy driving the fast shocks, which then transfers energy to the charged particles. Solar cosmic ray events can occur with or without magnetic storms (Halford et al, 2015(Halford et al, , 2016Foster et al, 2015). Some of the major extreme space weather topics will be addressed below.…”

Section: Energetic Particle Precipitation and Ozone Depletionmentioning

confidence: 99%

“…The reader should read Li et al (1993) for more details concerning the simulation and results. Related works on acceleration of magnetospheric electrons by shock impact on the magnetosphere can be found in Wygant et al (1994), Kellerman and Shprits (2012), Kellerman et al (2014), and Foster et al (2015).…”

Section: Interplanetary Shocks and The Formation Of New Radiation Beltsmentioning

confidence: 99%

The physics of space weather/solar-terrestrial physics (STP): what we know now and what the current and future challenges are

Tsurutani

Lakhina²,

Hajra

2020

Nonlin. Processes Geophys.

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Abstract. Major geomagnetic storms are caused by unusually intense solar wind southward magnetic fields that impinge upon the Earth's magnetosphere (Dungey, 1961). How can we predict the occurrence of future interplanetary events? Do we currently know enough of the underlying physics and do we have sufficient observations of solar wind phenomena that will impinge upon the Earth's magnetosphere? We view this as the most important challenge in space weather. We discuss the case for magnetic clouds (MCs), interplanetary sheaths upstream of interplanetary coronal mass ejections (ICMEs), corotating interaction regions (CIRs) and solar wind high-speed streams (HSSs). The sheath- and CIR-related magnetic storms will be difficult to predict and will require better knowledge of the slow solar wind and modeling to solve. For interplanetary space weather, there are challenges for understanding the fluences and spectra of solar energetic particles (SEPs). This will require better knowledge of interplanetary shock properties as they propagate and evolve going from the Sun to 1 AU (and beyond), the upstream slow solar wind and energetic “seed” particles. Dayside aurora, triggering of nightside substorms, and formation of new radiation belts can all be caused by shock and interplanetary ram pressure impingements onto the Earth's magnetosphere. The acceleration and loss of relativistic magnetospheric “killer” electrons and prompt penetrating electric fields in terms of causing positive and negative ionospheric storms are reasonably well understood, but refinements are still needed. The forecasting of extreme events (extreme shocks, extreme solar energetic particle events, and extreme geomagnetic storms (Carrington events or greater)) are also discussed. Energetic particle precipitation into the atmosphere and ozone destruction are briefly discussed. For many of the studies, the Parker Solar Probe, Solar Orbiter, Magnetospheric Multiscale Mission (MMS), Arase, and SWARM data will be useful.

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“…Some research has been done to study the GLEs detected in solar cycle 23, of which some work focused on individual events separately (e.g., Bieber et al, , , , ; Firoz et al, ; Grechnev et al, ; McCracken et al, ), but others systematically focused on the total GLEs (e.g., Gopalswamy et al, , ; Mewaldt et al, ; Reames, ). Gopalswamy et al () studied the flare and CME properties, and they found that the median value of flares associated with those GLEs except GLE61 is X3.8, which is far greater than that of all flares of solar cycle 23.…”

Section: Introductionmentioning

confidence: 99%

“…For example, if the Fe/O ratio is higher, the SEPs are considered from flare material instead of the shock acceleration from solar wind or coronal materials (e.g., Cane et al, 2003Cane et al, , 2006Reames, 1999). Some research has been done to study the GLEs detected in solar cycle 23, of which some work focused on individual events separately (e.g., Bieber et al, 2002Bieber et al, , 2004Bieber et al, , 2013Firoz et al, 2012;Grechnev et al, 2008;McCracken et al, 2008), but others systematically focused on the total GLEs (e.g., Gopalswamy et al, 2010Gopalswamy et al, , 2012Mewaldt et al, 2012;Reames, 2009). Gopalswamy et al (2010) studied the flare and CME properties, and they found that the median value of flares associated with those GLEs except GLE61 is X3.8, which is far greater than that of all flares of solar cycle 23.…”

Section: Introductionmentioning

confidence: 99%

Model of Energy Spectrum Parameters of Ground Level Enhancement Events in Solar Cycle 23

Qin

2018

JGR Space Physics

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Mewaldt et al. (2012) fitted the observations of the ground level enhancement (GLE) events during solar cycle 23 to the double power law equation to obtain the four spectral parameters, the normalization constant C, low‐energy power law slope γ1, high‐energy power law slope γ2, and break energy E0. There are 16 GLEs from which we select 13 for study by excluding some events with complicated situation. We analyze the four parameters with conditions of the corresponding solar events. According to solar event conditions, we divide the GLEs into two groups, one with strong acceleration by interplanetary shocks and another one without strong acceleration. By fitting the four parameters with solar event conditions we obtain models of the parameters for the two groups of GLEs separately. Therefore, we establish a model of energy spectrum of solar cycle 23 GLEs, which may be used in prediction in the future.

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An Interpretation of the Possible Mechanisms of Two Ground-Level Enhancement Events

Cited by 24 publications

References 51 publications

Electron and Proton Acceleration During the First Ground Level Enhancement Event of Solar Cycle 24

Electron and Proton Acceleration During the First Ground Level Enhancement Event of Solar Cycle 24

The physics of space weather/solar-terrestrial physics (STP): what we know now and what the current and future challenges are

Model of Energy Spectrum Parameters of Ground Level Enhancement Events in Solar Cycle 23

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