scholarly journals Unusual enhancement of ~ 30 MeV proton flux in an ICME sheath region

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Mitsuo Oka ◽  
Takahiro Obara ◽  
Nariaki V. Nitta ◽  
Seiji Yashiro ◽  
Daikou Shiota ◽  
...  
Keyword(s):  
Shock Front ◽  
Energetic Particle ◽  
Leading Edge ◽  
Solar Energetic Particle ◽  
Interplanetary Shock ◽  
Proton Event ◽  
Sheath Region ◽  
Time Profiles ◽  
Energetic Particle Flux ◽  
Mev Protons

AbstractIn gradual Solar Energetic Particle (SEP) events, shock waves driven by coronal mass ejections (CMEs) play a major role in accelerating particles, and the energetic particle flux enhances substantially when the shock front passes by the observer. Such enhancements are historically referred to as Energetic Storm Particle (ESP) events, but it remains unclear why ESP time profiles vary significantly from event to event. In some cases, energetic protons are not even clearly associated with shocks. Here, we report an unusual, short-duration proton event detected on 5 June 2011 in the compressed sheath region bounded by an interplanetary shock and the leading edge of the interplanetary CME (or ICME) that was driving the shock. While < 10 MeV protons were detected already at the shock front, the higher-energy (> 30 MeV) protons were detected about four hours after the shock arrival, apparently correlated with a turbulent magnetic cavity embedded in the ICME sheath region.

Unusual enhancement of ~30 MeV proton flux in an ICME sheath region

2021 ◽  
Author(s):  
Mitsuo Oka ◽  
Takahiro Obara ◽  
Nariaki Nitta ◽  
Seiji Yashiro ◽  
Daikou Shiota ◽  
...  
Keyword(s):  
Shock Front ◽  
Energetic Particle ◽  
Leading Edge ◽  
Solar Energetic Particle ◽  
Interplanetary Shock ◽  
Proton Event ◽  
Sheath Region ◽  
Time Profiles ◽  
Energetic Particle Flux ◽  
Mev Protons

&lt;p&gt;In gradual Solar Energetic Particle (SEP) events, shock waves driven by coronal mass ejections (CMEs) play a major role in accelerating particles, and the energetic particle flux enhances substantially when the shock front passes by the observer. Such enhancements are historically referred to as Energetic Storm Particle (ESP) events, but it remains unclear why ESP time profiles vary significantly from event to event. In some cases, energetic protons are not even clearly associated with shocks. Here we report an unusual, short-duration proton event detected on 5 June 2011 in the compressed sheath region bounded by an interplanetary shock and the leading-edge of the interplanetary CME (or ICME) that was driving the shock. While &lt;10 MeV protons were detected already at the shock front, the higher-energy (&gt;30 MeV) protons were detected about four hours after the shock arrival, apparently correlated with a turbulent magnetic cavity embedded in the ICME sheath region.&lt;/p&gt;

scholarly journals Cosmic ray and solar energetic particle flux in paleomagnetospheres

2010 ◽  
Vol 62 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Anja Stadelmann ◽  
Joachim Vogt ◽  
Karl-Heinz Glassmeier ◽  
May-Britt Kallenrode ◽  
Gerd-Hannes Voigt
Keyword(s):  
Energetic Particle ◽  
Particle Flux ◽  
Solar Energetic Particle ◽  
Cosmic Ray ◽  
Energetic Particle Flux

scholarly journals Recurrent Solar Energetic Particle Flux Enhancements Observed near Earth and Mars

2020 ◽  
Vol 902 (1) ◽  
pp. 13
Author(s):  
C. Krishnaprasad ◽  
Smitha V. Thampi ◽  
Anil Bhardwaj ◽  
Christina O. Lee ◽  
K. Kishore Kumar ◽  
...  
Keyword(s):  
Energetic Particle ◽  
Particle Flux ◽  
Solar Energetic Particle ◽  
Energetic Particle Flux

scholarly journals Distinguishing the Sources

2021 ◽  
pp. 49-69
Author(s):  
Donald V. Reames
Keyword(s):  
Magnetic Field ◽  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Active Regions ◽  
High Energy ◽  
Injection Time ◽  
Closed Loops ◽  
Compact Source ◽  
Time Profiles ◽  
Onset Timing

AbstractOur discussion of history has covered many of the observations that have led to the ideas of acceleration by shock waves or by magnetic reconnection in gradual and impulsive solar energetic particle (SEP) events, respectively. We now present other compelling observations, including onset timing, SEP-shock correlations, injection time profiles, high-energy spectral knees, e/p ratios, and intensity dropouts caused by a compact source, that have helped clarify these acceleration mechanisms and sources. However, some of the newest evidence now comes from source-plasma temperatures. In this and the next two chapters, we will find that impulsive events come from solar active regions at ≈ 3 MK, controlling ionization states Q, hence A/Q, and, in most gradual events, shocks accelerate ambient coronal material from ≤1.6 MK. When SEPs are trapped on closed loops they supply the energy for flares. In addition to helping to define their own origin, SEPs also probe the structure of the interplanetary magnetic field.

scholarly journals Superdiffusive and ballistic propagation of protons in solar energetic particle events

2010 ◽  
Vol 6 (S274) ◽  
pp. 198-200
Author(s):  
Enrico M. Trotta ◽  
Gaetano Zimbardo
Keyword(s):  
Energetic Particle ◽  
Ballistic Transport ◽  
Solar Energetic Particle ◽  
Mean Free Path ◽  
Time Profile ◽  
Asymptotic Regime ◽  
Time Profiles ◽  
Solar Energetic Particle Events ◽  
Using Data ◽  
Soho Spacecraft

AbstractIn this work we show that protons can exhibit both superdiffusive and ballistic propagation, at variance with standard diffusion. We carry out an analysis of impulsive solar energetic particle (SEP) events, for which the observed time profile of energetic particle fluxes represent the propagator of the corresponding transport equation. We show that in the case of superdiffusive or ballistic transport the propagator in the time asymptotic regime has a power law form, and that a fit of the observed time profiles allows to determine the transport regime. Using data obtained from ACE and SoHO spacecraft, two proton and electron events, which exhibit both superdiffusive and ballistic transport, will be shown. The finding of these anomalous regimes implies that no finite mean free path can be defined.

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