A Primer on Focused Solar Energetic Particle Transport
- PDF / 7,240,929 Bytes
- 57 Pages / 439.37 x 666.142 pts Page_size
- 75 Downloads / 236 Views
A Primer on Focused Solar Energetic Particle Transport Basic Physics and Recent Modelling Results Jabus van den Berg1,2 · Du Toit Strauss1 Frederic Effenberger3,4
·
Received: 23 June 2020 / Accepted: 15 November 2020 © Springer Nature B.V. 2020
Abstract The basics of focused transport as applied to solar energetic particles are reviewed, paying special attention to areas of common misconception. The micro-physics of charged particles interacting with slab turbulence are investigated to illustrate the concept of pitch-angle scattering, where after the distribution function and focused transport equation are introduced as theoretical tools to describe the transport processes and it is discussed how observable quantities can be calculated from the distribution function. In particular, two approximations, the diffusion-advection and the telegraph equation, are compared in simplified situations to the full solution of the focused transport equation describing particle motion along a magnetic field line. It is shown that these approximations are insufficient to capture the complexity of the physical processes involved. To overcome such limitations, a finite-difference model, which is open for use by the public, is introduced to solve the focused transport equation. The use of the model is briefly discussed and it is shown how the model can be applied to reproduce an observed solar energetic electron event, providing insights into the acceleration and transport processes involved. Past work and literature on the application of these concepts are also reviewed, starting with the most basic models and building up to more complex models. Keywords Solar energetic particles · Particle transport · Particle acceleration · Focused transport · Numerical modelling · Review
B J. van den Berg
[email protected] D.T. Strauss [email protected] F. Effenberger [email protected]
1
Centre for Space Research, North-West University, Potchefstroom, South Africa
2
South African National Space Agency, Hermanus, South Africa
3
GFZ German Research Centre For Geosciences, Potsdam, Germany
4
Bay Area Environmental Research Institute, NASA Research Park, Moffett Field, CA, USA
146
Page 2 of 57
J. van den Berg et al.
1 Introduction Solar energetic particles (SEPs) are one of the key subjects in heliospheric physics, receiving even more interest in the last couple of years, mostly due to space missions focusing on the Sun, such as the Parker Solar Probe (launched on 11 August 2018; http://parkersolarprobe. jhuapl.edu/index.php; Fox et al. 2016) and the Solar Orbiter mission (launched on 10 February 2020; http://sci.esa.int/solar-orbiter; Müller et al. 2013). Their importance is not only related to their character as highly energetic test particles, tracing the heliospheric plasma environment between their source close to the Sun and the observer, but also to their potential impact on space hardware and interplanetary travel by humans. A number of excellent and mostly up to date reviews on general SEP properties and their o
Data Loading...
