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Found 15 entries in the Bibliography.
Showing entries from 1 through 15
| 2023 |
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Transport of Cosmic-Ray Electrons from 1 au to the Sun Gamma rays are produced by cosmic-ray (CR) protons interacting with the particles at the solar photosphere and by CR electrons and positrons (CRes) via inverse Compton scattering of solar photons. The former comes from the solar disk while the latter extends beyond the disk. Evaluation of these emissions requires the flux and spectrum of CRs in the vicinity of the Sun, while most observations provide flux and spectra near the Earth, at around 1 au from the Sun. Past estimates of the quiet Sun gamma- ray emission use phenomen ... Petrosian, Vah\; Orlando, Elena; Strong, Andrew; Published by: \apj Published on: jan YEAR: 2023 DOI: 10.3847/1538-4357/aca474 Parker Data Used; cosmic rays; Solar wind; interplanetary turbulence; 329; 1534; 830; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics |
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The Modulation of Anomalous and Galactic Cosmic-Ray Oxygen over Successive Solar Cycle Minima Both the recent 2009 and 2020 solar minima were classified as unusually quiet and characterized with unusually high galactic cosmic-ray (GCR) levels. However, unlike the trends from previous decades, in which anomalous cosmic-ray (ACR) and GCR levels strongly agreed, the ACR intensities did not reach such high, record- setting levels. This discrepancy between the behavior of GCRs and ACRs is investigated in this work by simulating the acceleration and transport of GCR and ACR oxygen under different transport conditions. Afte ... Strauss, R.~D.; Leske, R.~A.; Rankin, J.~S.; Published by: \apj Published on: feb YEAR: 2023 DOI: 10.3847/1538-4357/acb53d Parker Data Used; Galactic cosmic rays; Heliosphere; Termination shock; Interplanetary particle acceleration; 567; 711; 1690; 826; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Space Physics |
| 2022 |
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Galactic Cosmic-Ray Propagation in the Inner Heliosphere: Improved Force-field Model Li, Jung-Tsung; Beacom, John; Peter, Annika; Published by: \apj Published on: sep YEAR: 2022 DOI: 10.3847/1538-4357/ac8cf3 Parker Data Used; cosmic rays; Galactic cosmic rays; Gamma-ray astronomy; Gamma-ray observatories; Magnetohydrodynamics; Plasma astrophysics; Particle astrophysics; High energy astrophysics; Solar Physics; interplanetary turbulence; 329; 567; 628; 632; 1964; 1261; 96; 739; 1476; 830; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; High Energy Physics - Phenomenology; Physics - Plasma Physics; Physics - Space Physics |
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Relativistic Particle Transport and Acceleration in Structured Plasma Turbulence We discuss the phenomenon of energization of relativistic charged particles in three-dimensional incompressible MHD turbulence and the diffusive properties of the motion of the same particles. We show that the random electric field induced by turbulent plasma motion leads test particles moving in a simulated box to be accelerated in a stochastic way, a second-order Fermi process. A small fraction of these particles happen to be trapped in large- scale structures, most likely formed due to the interaction of islands in the tu ... Pezzi, Oreste; Blasi, Pasquale; Matthaeus, William; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac5332 Parker Data Used; Magnetohydrodynamics; cosmic rays; Particle astrophysics; 1964; 329; 96; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics |
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The acceleration of charged particles by interplanetary shocks (IPs) can drain a nonnegligible fraction of the plasma pressure. In this study, we have selected 17 IPs observed in situ at 1 au by the Advanced Composition Explorer and the Wind spacecraft, and 1 shock at 0.8 au observed by Parker Solar Probe. We have calculated the time-dependent partial pressure of suprathermal and energetic particles (smaller and greater than 50 keV for protons and 30 keV for electrons, respectively) in both the upstream and downstream region ... David, Liam; Fraschetti, Federico; Giacalone, Joe; Wimmer-Schweingruber, Robert; Berger, Lars; Lario, David; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac54af Parker Data Used; Interplanetary shocks; Interplanetary particle acceleration; Space plasmas; 829; 826; 1544; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics; Physics - Space Physics |
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The transport of energetic charged particles (e.g., cosmic rays) in turbulent magnetic fields is usually characterized in terms of the diffusion parallel and perpendicular to a large-scale (or mean) magnetic field. The nonlinear guiding center theory has been a prominent perpendicular diffusion theory. A recent version of this theory, based on the random ballistic spreading of magnetic field lines and a backtracking correction (RBD/BC), has shown good agreement with test particle simulations for a two-component magnetic turb ... Snodin, A.~P.; Jitsuk, T.; Ruffolo, D.; Matthaeus, W.~H.; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac6e6d Parker Data Used; cosmic rays; magnetic fields; Particle astrophysics; 329; 994; 96; Physics - Plasma Physics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Space Physics |
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On the Conservation of Turbulence Energy in Turbulence Transport Models Zank et al. developed models describing the transport of low-frequency incompressible and nearly incompressible turbulence in inhomogeneous flows. The formalism was based on expressing the fluctuating variables in terms of the Elsässar variables and then taking moments subject to various closure hypotheses. The turbulence transport models are different according to whether the plasma beta regime is large, of order unity, or small. Here, we show explicitly that the three sets of turbulence transport models admit a conser ... Wang, B.; Zank, G.~P.; Adhikari, L.; Zhao, L.; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac596e Parker Data Used; Magnetohydrodynamics; interplanetary turbulence; 1964; 830; Physics - Plasma Physics; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics; Physics - Fluid Dynamics |
| 2021 |
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Energetic particles, such as stellar cosmic rays, produced at a heightened rate by active stars (like the young Sun) may have been important for the origin of life on Earth and other exoplanets. Here, we compare, as a function of stellar rotation rate (Ω), contributions from two distinct populations of energetic particles: stellar cosmic rays accelerated by impulsive flare events and Galactic cosmic rays. We use a 1.5D stellar wind model combined with a spatially 1D cosmic ray transport model. We formulate the evolution of ... Rodgers-Lee, D.; Taylor, A.; Vidotto, A.; Downes, T.; Published by: Monthly Notices of the Royal Astronomical Society Published on: 06/2021 YEAR: 2021 DOI: 10.1093/mnras/stab935 diffusion; methods: numerical; Sun: evolution; stars: magnetic field; cosmic rays; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Earth and Planetary Astrophysics; Astrophysics - High Energy Astrophysical Phenomena |
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Electron Acceleration during Macroscale Magnetic Reconnection The first self-consistent simulations of electron acceleration during magnetic reconnection in a macroscale system are presented. Consistent with solar flare observations, the spectra of energetic electrons take the form of power laws that extend more than two decades in energy. The drive mechanism for these nonthermal electrons is Fermi reflection in growing and merging magnetic flux ropes. A strong guide field suppresses the production of nonthermal electrons by weakening the Fermi drive mechanism. For a weak guide field t ... Arnold, H.; Drake, J.; Swisdak, M.; Guo, F.; Dahlin, J.; Chen, B.; Fleishman, G.; Glesener, L.; Kontar, E.; Phan, T.; Shen, C.; Published by: Physical Review Letters Published on: 04/2021 YEAR: 2021 DOI: 10.1103/PhysRevLett.126.135101 Parker Data Used; Physics - Plasma Physics; Astrophysics - High Energy Astrophysical Phenomena |
| 2020 |
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Bi-directional streaming of particles accelerated at the STEREO-A shock on 2008 March 9 Fraschetti, F.; Giacalone, J.; Published by: \mnras Published on: 12/2020 YEAR: 2020 DOI: 10.1093/mnras/staa3021 Parker Data Used; acceleration of particles; shock waves; turbulence; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Novel aspects of cosmic ray diffusion in synthetic magnetic turbulence Dundovic, Andrej; Pezzi, Oreste; Blasi, Pasquale; Evoli, Carmelo; Matthaeus, William; Published by: \prd Published on: 11/2020 YEAR: 2020 DOI: 10.1103/PhysRevD.102.103016 Parker Data Used; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics; Physics - Space Physics |
| 2019 |
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A computational model for exploring particle acceleration during reconnection in macroscale systems Drake, J.~F.; Arnold, H.; Swisdak, M.; Dahlin, J.~T.; Published by: Physics of Plasmas Published on: 01/2019 YEAR: 2019 DOI: 10.1063/1.5058140 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; Physics - Plasma Physics |
| 2018 |
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Solar corona heating by axion quark nugget dark matter In this work we advocate for the idea that two seemingly unrelated 80-year-old mysteries\textemdashthe nature of dark matter and the high temperature of the million degree solar corona\textemdashmay have resolutions that lie within the same physical framework. The current paradigm is that the corona is heated by nanoflares, which were originally proposed as miniature versions of the observed solar flares. It was recently suggested that the nanoflares could be identified as annihilation events of the nuggets from the axion ... Raza, Nayyer; Van Waerbeke, Ludovic; Zhitnitsky, Ariel; Published by: Physical Review D Published on: 11/2018 YEAR: 2018 DOI: 10.1103/PhysRevD.98.103527 Astrophysics - Cosmology and Nongalactic Astrophysics; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics; High Energy Physics - Phenomenology; parker solar probe; Solar Probe Plus |
| 2017 |
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Charged Particle Diffusion in Isotropic Random Magnetic Fields Subedi, P.; Sonsrettee, W.; Blasi, P.; Ruffolo, D.; Matthaeus, W.~H.; Montgomery, D.; Chuychai, P.; Dmitruk, P.; Wan, M.; Parashar, T.~N.; Chhiber, R.; Published by: \apj Published on: 03/2017 YEAR: 2017 DOI: 10.3847/1538-4357/aa603a Parker Data Used; astroparticle physics; cosmic rays; diffusion; magnetic fields; scattering; turbulence; Physics - Space Physics; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics |
| 2015 |
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Localized enhancements of energetic particles at oblique collisionless shocks Fraschetti, F.; Giacalone, J.; Published by: \mnras Published on: 04/2015 YEAR: 2015 DOI: 10.1093/mnras/stv247 Parker Data Used; turbulence; cosmic rays; ISM: magnetic fields; Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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