Mutual Obligation? Regulating by Supervision and Surveillance in Australian Income Support P

Fopp, Rodney

doi:10.24908/ss.v3i1.3323

Cited by 19 publications

(24 citation statements)

References 19 publications

(12 reference statements)

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“…We study the acceleration of particles by numerically integrating the Parker transport equation (Parker 1965),…”

Section: Particle Accelerationmentioning

confidence: 99%

“…For comparison, we also consider a case with only a radial magnetic field from the center of the Sun. We study the acceleration of protons in the shockstreamer system by numerically solving the Parker transport equation (Parker 1965) through a stochastic integration method (e.g., Giacalone & Neugebauer 2008;Guo et al 2010;Senanayake & Florinski 2013).…”

Section: Numerical Modelmentioning

confidence: 99%

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The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Kong

Guo

Giacalone

et al. 2017

ApJ

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Recent observations have shown that coronal shocks driven by coronal mass ejections can develop and accelerate particles within several solar radii in large solar energetic particle (SEP) events. Motivated by this, we present an SEP acceleration study that including the process in which a fast shock propagates through a streamer-like magnetic field with both closed and open field lines in the low corona region. The acceleration of protons is modeled by numerically solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that particles can be sufficiently accelerated to up to several hundred MeV within 2-3 solar radii. When the shock propagates through a streamer-like magnetic field, particles are more efficiently accelerated compared to the case with a simple radial magnetic field, mainly due to perpendicular shock geometry and the natural trapping effect of closed magnetic fields. Our results suggest that the coronal magnetic field configuration is an important factor for producing large SEP events. We further show that the coronal magnetic field configuration strongly influences the distribution of energetic particles, leading to different locations of source regions along the shock front where most high-energy particles are concentrated. This work may have strong implications for SEP observations. The upcoming Parker Solar Probe will provide in situ observations for the distribution of energetic particles in the coronal shock region, and test the results of the study.

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“…We study the acceleration of particles by numerically integrating the Parker transport equation (Parker 1965),…”

Section: Particle Accelerationmentioning

confidence: 99%

Section: Numerical Modelmentioning

confidence: 99%

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

Kong

Guo

Giacalone

et al. 2017

ApJ

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“…A full 3D modulation model is used to compute differential intensities of GCR protons at the Earth, and is based on the numerical solution of the heliospheric transport equation from Parker (1965):…”

Section: Modeling the Pamela Proton Spectramentioning

confidence: 99%

New Modeling of Galactic Proton Modulation During the Minimum of Solar Cycle 23/24

Vos

Potgieter

2015

ApJ

160

156

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During the recent prolonged solar minimum of cycle 23/24, the PAMELA detector measured 27-day averaged Galactic proton energy spectra over the energy range that is important for solar modulation. By comparing these spectra to computed spectra from a three-dimensional model that contains all of the important heliospheric modulation processes, the recent minimum can be studied in detail from a modulation perspective. This was done by setting up a realistic heliosphere in the model, and reproducing a representative selection of seven intermittent PAMELA spectra, separated by approximately six months, from 2006 July to 2009 December. Additionally, a new very local interstellar proton spectrum was constructed using measurements below 600 MeV from Voyager 1, taken beyond the heliopause, combined with PAMELA and AMS-02 measurements above 30 GeV at the Earth. As a result of the extreme minimum modulation conditions that governed the recent solar minimum, the highest ever Galactic cosmic ray spectrum at Earth was observed by PAMELA at the end of 2009. It was found that, apart from the self-consistent changes in the heliospheric current sheet and the heliospheric magnetic field over time, additional increases in the mean free paths during this period were required below~4 GV in order to reproduce the intensities observed by PAMELA.

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“…When particles interact with the shock, they may undergo first-order Fermi acceleration or/and drift acceleration (for non-parallel shocks), and eventually they experience a cumulative acceleration effect during multiple shock encounters. Conventionally, the DSA process is described by the diffusion-convection equation (Parker 1965; also called the Parker equation) that governs the evolution of the pitchangle-averaged distribution function of energetic particles, with the basic assumption that the distribution function of particles is isotropic to first order (O(u/v)). It requires that particle velocities measured in the local plasma frame be far larger than the plasma flow speed in the shock frame (Zank et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Acceleration of Low-Energy Ions at Parallel Shocks With a Focused Transport Model

Zuo

Zhang

Rassoul

2013

ApJ

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We present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by parallel shocks with a focused transport model. The focused transport equation contains all necessary physics of shock acceleration, but avoids the limitation of diffusive shock acceleration (DSA) that requires a small pitch angle anisotropy. This simulation verifies that the particles with speeds of a fraction of to a few times the shock speed can indeed be directly injected and accelerated into the DSA regime by parallel shocks. At higher energies starting from a few times the shock speed, the energy spectrum of accelerated particles is a power law with the same spectral index as the solution of standard DSA theory, although the particles are highly anisotropic in the upstream region. The intensity, however, is different from that predicted by DSA theory, indicating a different level of injection efficiency. It is found that the shock strength, the injection speed, and the intensity of an electric cross-shock potential (CSP) jump can affect the injection efficiency of the low-energy particles. A stronger shock has a higher injection efficiency. In addition, if the speed of injected particles is above a few times the shock speed, the produced power-law spectrum is consistent with the prediction of standard DSA theory in both its intensity and spectrum index with an injection efficiency of 1. CSP can increase the injection efficiency through direct particle reflection back upstream, but it has little effect on the energetic particle acceleration once the speed of injected particles is beyond a few times the shock speed. This test particle simulation proves that the focused transport theory is an extension of DSA theory with the capability of predicting the efficiency of particle injection.

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Mutual Obligation? Regulating by Supervision and Surveillance in Australian Income Support P

Cited by 19 publications

References 19 publications

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures

New Modeling of Galactic Proton Modulation During the Minimum of Solar Cycle 23/24

Acceleration of Low-Energy Ions at Parallel Shocks With a Focused Transport Model

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