Cosmic Rays and Energetic Particles

1998 ◽  
pp. 257-277
Keyword(s):  
Cosmic Rays ◽  
Energetic Particles

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 Ulysses COSPIN observations of cosmic rays and solar energetic particles from the South Pole to the North Pole of the Sun during solar maximum

2003 ◽  
Vol 21 (6) ◽  
pp. 1217-1228 ◽  
Author(s):  
R. B. McKibben ◽  
J. J. Connell ◽  
C. Lopate ◽  
M. Zhang ◽  
J. D. Anglin ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Solar Maximum ◽  
Cosmic Ray ◽  
Energetic Particles ◽  
Solar Energetic Particles ◽  
Polar Regions ◽  
The Sun ◽  
The South ◽  
The North ◽  
Inner Heliosphere

Abstract. In 2000–2001 Ulysses passed from the south to the north polar regions of the Sun in the inner heliosphere, providing a snapshot of the latitudinal structure of cosmic ray modulation and solar energetic particle populations during a period near solar maximum.  Observations from the COSPIN suite of energetic charged particle telescopes show that latitude variations in the cosmic ray intensity in the inner heliosphere are nearly non-existent near solar maximum, whereas small but clear latitude gradients were observed during the similar phase of Ulysses’ orbit near the 1994–95 solar minimum. At proton energies above ~10 MeV and extending up to >70 MeV, the intensities are often dominated by Solar Energetic Particles (SEPs) accelerated near the Sun in association with intense solar flares and large Coronal Mass Ejections (CMEs). At lower energies the particle intensities are almost constantly enhanced above background, most likely as a result of a mix of SEPs and particles accelerated by interplanetary shocks. Simultaneous high-latitude Ulysses and near-Earth observations show that most events that produce large flux increases near Earth also produce flux increases at Ulysses, even at the highest latitudes attained. Particle anisotropies during particle onsets at Ulysses are typically directed outwards from the Sun, suggesting either acceleration extending to high latitudes or efficient cross-field propagation somewhere inside the orbit of Ulysses. Both cosmic ray and SEP observations are consistent with highly efficient transport of energetic charged particles between the equatorial and polar regions and across the mean interplanetary magnetic fields in the inner heliosphere.Key words. Interplanetary physics (cosmic rays) – Solar physics, astrophysics and astronomy (energetic particles; flares and mass ejections)

Modelling the influence of high-energy radiation on the atmospheric composition of the hot Jupiter HD 189733b

2021 ◽  
Author(s):  
Patrick Barth ◽  
Christiane Helling ◽  
Eva E. Stüeken ◽  
Vincent Bourrier ◽  
Nathan Mayne ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Atmospheric Composition ◽  
Cloud Formation ◽  
Fine Grid ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Hot Jupiter

<p>Hot Jupiters provide valuable natural laboratories for studying potential contributions of high-energy radiation to prebiotic synthesis in the atmospheres of exoplanets. HD 189733b, a hot Jupiter orbiting a K star, is one of the most studied and best observed exoplanets. We combine XUV observations and 3D climate simulations to model the atmospheric composition and kinetic chemistry with the STAND2019 network. We show how XUV radiation, cosmic rays (CR), and stellar energetic particles (SEP) influence the chemistry of the atmosphere. We explore the effect that the change in the XUV radiation has over time, and we identify key atmospheric signatures of an XUV, CR, and SEP influx. 3D simulations of HD 189733b's atmosphere with the 3D Met Office Unified Model provide a fine grid of pressure-temperature profiles, consistently taking into account kinetic cloud formation. We apply <em>HST</em> and <em>XMM-Newton/Swift</em> observations obtained by the MOVES programmewhich provide combined X-ray and ultraviolet (XUV) spectra of the host star HD 189733 at 4 different points in time. We find that the differences in the radiation field between the irradiated dayside and the shadowed nightside lead to stronger changes in the chemical abundances than the variability of the host star's XUV emission. We identify ammonium (NH<sub>4</sub><sup>+</sup>) and oxonium (H<sub>3</sub>O<sup>+</sup>) as fingerprint ions for the ionization of the atmosphere by both galactic cosmic rays and stellar particles. All considered types of high-energy radiation have an enhancing effect on the abundance of key organic molecules such as hydrogen cyanide (HCN), formaldehyde (CH<sub>2</sub>O), and ethylene (C<sub>2</sub>H<sub>4</sub>). The latter two are intermediates in the production pathway of the amino acid glycine (C<sub>2</sub>H<sub>5</sub>NO<sub>2</sub>) and abundant enough to be potentially detectable by <em>JWST</em>. Ultimately, we show that high energy processes potentially play an important role in prebiotic chemistry.</p><p>P Barth et al., MOVES IV. Modelling the influence of stellar XUV-flux, cosmic rays, and stellar energetic particles on the atmospheric composition of the hot Jupiter HD 189733b, <em>Monthly Notices of the Royal Astronomical Society</em>, in press, DOI:10.1093/mnras/staa3989</p>

scholarly journals Hydrogen molecular ions and the violent birth of the Solar System

2019 ◽  
Vol 377 (2154) ◽  
pp. 20180403 ◽  
Author(s):  
Cecilia Ceccarelli ◽  
Cecile Favre ◽  
Ana López-Sepulcre ◽  
Francesco Fontani
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Past History ◽  
Classical Problem ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Molecular Ions ◽  
Observational Constraints ◽  
The Past ◽  
History Of

Many pieces of evidence indicate that the Solar System youth was marked by violent processes: among others, high fluxes of energetic particles (greater than or equal to 10 MeV) are unambiguously recorded in meteoritic material, where an overabundance of the short-lived 10 Be products is measured. Several hypotheses have been proposed to explain from where these energetic particles originate, but there is no consensus yet, mostly because of the scarcity of complementary observational constraints. In general, the reconstruction of the past history of the Solar System is best obtained by simultaneously considering what we know of it and of similar systems nowadays in formation. However, when it comes to studying the presence of energetic particles in young forming stars, we encounter the classical problem of the impossibility of directly detecting them toward the emitting source (analogously to what happens to galactic cosmic rays). Yet, exploiting the fact that energetic particles, such as cosmic rays, create H 3 + and that an enhanced abundance of H 3 + causes dramatic changes on the overall gas chemical composition, we can indirectly estimate the flux of energetic particles. This contribution provides an overview of the search for solar-like protostars permeated by energetic particles and the discovery of a protocluster, OMC-2 FIR4, where the phenomenon is presently occurring. This article is part of a discussion meeting issue ‘Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond’.

Cosmic rays—astronomy with energetic particles

Physics Today ◽  
1974 ◽  
Vol 27 (10) ◽  
pp. 23-32 ◽  
Author(s):  
Peter Meyer ◽  
Reuven Ramaty ◽  
William R. Webber
Keyword(s):  
Cosmic Rays ◽  
Energetic Particles

Transport of neutrinos, radiation and energetic particles in accretion flows

1982 ◽  
Vol 383 (1785) ◽  
pp. 409-437 ◽  
Keyword(s):  
Cosmic Rays ◽  
Electromagnetic Radiation ◽  
Gravitational Collapse ◽  
Charged Particles ◽  
Energetic Particles ◽  
Compact Objects ◽  
Red Giants ◽  
X Ray ◽  
Accretion Flows

The equations describing the transport of suprathermal charged particles, electromagnetic radiation and neutrinos across accretion flows onto compact objects are solved analytically, the effects of shocks in the flow being included. These solutions are used in discussing three illustrative astrophysical examples: acceleration of cosmic rays, generation of spectral continua in quasars and the effect of neutrinos during the collapse of supernova precursors. The main results are: ( а ) Accretion flows with shocks accelerate cosmic rays very efficiently up to the highest energies. ( b ) The emergent spectra of electromagnetic radiation from such flows reproduce the observed spectra of quasars from infrared to the hard X-ray region. ( c ) The neutrinos in the collapsing cores of red giants develop a very hard non-thermal tail in their distribution facilitating the rebound of the gravitational collapse leading to the supernovae.

scholarly journals Impact of cosmic rays and solar energetic particles on the Earth’s ionosphere and atmosphere

2013 ◽  
Vol 3 ◽  
pp. A14 ◽  
Author(s):  
Peter I.Y. Velinov ◽  
Simeon Asenovski ◽  
Karel Kudela ◽  
Jan Lastovicka ◽  
Lachezar Mateev ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
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.

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