The Current Status in Our Understanding of Energetic Particles, Coronal Mass Ejections, and Flares

2013 ◽  
pp. 205-215 ◽  
Author(s):  
H. V. Cane
Keyword(s):  
Coronal Mass Ejections ◽  
Energetic Particles ◽  
Current Status

scholarly journals On particle acceleration and transport in plasmas in the Galaxy: theory and observations

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Elena Amato ◽  
Sabrina Casanova
Keyword(s):  
Particle Acceleration ◽  
Cosmic Rays ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Quality Data ◽  
Current Status ◽  
The Earth ◽  
The Galaxy ◽  
Formation And Evolution ◽  
Galaxy Assembly

Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU scale relevant for the formation and evolution of stars and planets to the Mpc scale involved in Galaxy assembly. We reveal the presence of energetic particles in many classes of astrophysical sources thanks to their production of non-thermal radiation, and we detect them directly at the Earth as cosmic rays. In the last two decades both direct and indirect observations have provided us a wealth of new, high-quality data about cosmic rays and their interactions both in sources and during propagation, in the Galaxy and in the Solar System. Some of the new data have confirmed existing theories about particle acceleration and propagation and their interplay with the environment in which they occur. Some others have brought about interesting surprises, whose interpretation is not straightforward within the standard framework and may require a change of paradigm in terms of our ideas about the origin of cosmic rays of different species or in different energy ranges. In this article, we focus on cosmic rays of galactic origin, namely with energies below a few petaelectronvolts, where a steepening is observed in the spectrum of energetic particles detected at the Earth. We review the recent observational findings and the current status of the theory about the origin and propagation of galactic cosmic rays.

scholarly journals Predicting the geoeffective properties of coronal mass ejections: current status, open issues and path forward

2019 ◽  
Vol 377 (2148) ◽  
pp. 20180096 ◽  
Author(s):  
A. Vourlidas ◽  
S. Patsourakos ◽  
N. P. Savani
Keyword(s):  
Space Weather ◽  
Coronal Mass Ejections ◽  
Technology Development ◽  
Action Plan ◽  
Current Status ◽  
Weather Impact ◽  
Solar Eruptions ◽  
Holding Back ◽  
Open Issues ◽  
Made In

Much progress has been made in the study of coronal mass ejections (CMEs), the main drivers of terrestrial space weather thanks to the deployment of several missions in the last decade. The flow of energy required to power solar eruptions is beginning to be understood. The initiation of CMEs is routinely observed with cadences of tens of seconds with arc-second resolution. Their inner heliospheric evolution can now be imaged and followed routinely. Yet relatively little progress has been made in predicting the geoeffectiveness of a particular CME. Why is that? What are the issues holding back progress in medium-term forecasting of space weather? To answer these questions, we review, here, the measurements, status and open issues on the main CME geoeffective parameters; namely, their entrained magnetic field strength and configuration, their Earth arrival time and speed, and their mass (momentum). We offer strategies for improving the accuracy of the measurements and their forecasting in the near and mid-term future. To spark further discussion, we incorporate our suggestions into a top-level draft action plan that includes suggestions for sensor deployment, technology development and modelling/theory improvements. This article is part of the theme issue ‘Solar eruptions and their space weather impact’.

scholarly journals How Efficient are Coronal Mass Ejections at Accelerating Solar Energetic Particles?

2008 ◽  
Author(s):  
R. A. Mewaldt ◽  
C. M. S. Cohen ◽  
J. Giacalone ◽  
G. M. Mason ◽  
E. E. Chollet ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Energetic Particles ◽  
Solar Energetic Particles

scholarly journals Energetic Particles in the Local Bubble

1997 ◽  
Vol 166 ◽  
pp. 177-186 ◽  
Author(s):  
G.E. Morfill ◽  
M.J. Freyberg
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Current Status ◽  
Length Variation ◽  
Local Bubble ◽  
Cosmic Ray Intensity ◽  
Interstellar Clouds ◽  
Proton Intensity ◽  
Path Lengths

AbstractThe current status of observations of energetic particles in the “local bubble” is reviewed. This includes primarily “direct” measurements of cosmic rays made in the Solar System, but also the “remote sensing” made possible by observing cosmic ray produced γ-rays in the nearby interstellar clouds. Since the energetic events responsible for the formation of our local bubble may also have produced copious amounts of cosmic rays, fossil records are examined to determine whether there is a corresponding signature. The observations show that: 1) the cosmic ray (proton) intensity is fairly homogeneous throughout the local bubble and its adjacent interstellar clouds, 2) there is some evidence for a “recent” local cosmic ray injection about 40,000 years ago, 3) on longer time scales (a few million years) the cosmic ray intensity was constant within a factor two, 4) there is apparently some “activity” in the Orion cloud, as evidenced by low energy γ-ray signatures, and 5) there are two unexplained observations – the variations in the energy spectra, in particular the significantly flatter spectrum of heavy cosmic rays (Fe) and the matter path length variation, which yields consistently larger path lengths for the lighter elements (H, He). It is suggested that these observations are compatible with two cosmic ray populations – an older one in equilibrium with losses from the galaxy and a younger one which is not yet strongly affected by losses. The latter could be a cosmic ray signature of the formation of the local bubble.

scholarly journals Very narrow coronal mass ejections producing solar energetic particles

2018 ◽  
Vol 619 ◽  
pp. A34 ◽  
Author(s):  
K. Bronarska ◽  
M. S. Wheatland ◽  
N. Gopalswamy ◽  
G. Michalek
Keyword(s):  
Coronal Mass Ejections ◽  
Weather Forecasting ◽  
Coronal Holes ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Low Energy ◽  
Angular Width ◽  
Arrival Times ◽  
Kolmogorov Smirnov ◽  
Solar Particles

Aims. Our main aim is to study the relationship between low-energy solar particles (energies below 1 MeV) and very narrow coronal mass ejections (“jets” with angular width ≤ 20°). Methods. For this purpose, we considered 125 very narrow coronal mass ejections (CMEs) from 1999 to 2003 that are potentially associated with low-energy solar particles (LESPs). These events were chosen on the basis of their source location. We studied only very narrow CMEs at the western limb, which are expected to have good magnetic connectivity with Earth. Results. We found 24 very narrow CMEs associated with energetic particles such as ions (protons and 3He), electrons, or both. We show that arrival times at Earth of energetic particles are consistent with onset times of the respective CMEs, and that in the same time intervals, there are no other potential sources of energetic particles. We also demonstrate statistical differences for the angular width distributions using the Kolmogorov–Smirnov test for angular widths for these 24 events. We consider a coherent sample of jets (mostly originating from boundaries of coronal holes) to identify properties of events that produce solar energetic particles (velocities, widths, and position angles). Our study presents a new approach and result: very narrow CMEs can generate low-energy particles in the vicinity of Earth without other activity on the Sun. The results could be very useful for space weather forecasting.

scholarly journals Current status and possible extension of the global neutron monitor network

2020 ◽  
Vol 10 ◽  
pp. 17
Author(s):  
Alexander Mishev ◽  
Ilya Usoskin
Keyword(s):  
Space Weather ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Ground Level ◽  
Solar Proton ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Current Status ◽  
Flight Altitude ◽  
Ground Level Enhancements

The global neutron monitor network has been successfully used over several decades to study cosmic ray variations and fluxes of energetic solar particles. Nowadays, it is used also for space weather purposes, e.g. alerts and assessment of the exposure to radiation. Here, we present the current status of the global neutron monitor network. We discuss the ability of the global neutron monitor network to study solar energetic particles, specifically during large ground level enhancements. We demonstrate as an example, the derived solar proton characteristics during ground level enhancements GLE #5 and the resulting effective dose over the globe at a typical commercial jet flight altitude of 40 kft (≈12,200 m) above sea level. We present a plan for improvement of space weather services and applications of the global neutron monitor network, specifically for studies related to solar energetic particles, namely an extension of the existing network with several new monitors. We discuss the ability of the optimized global neutron monitor network to study various populations of solar energetic particles and to provide reliable space weather services.

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