High-Energy Astrophysics

This course is an introduction to the acceleration, propagation, and radiation mechanisms of energetic particles in astrophysical media. It will cover the fundamental concepts in this field.

Gain a basic understanding of the processes of acceleration and propagation of astroparticles in magnetized media. The course will be taught in a lecture format, but will be supplemented by exercises with answer keys to be completed at home. Students will also be required to write a reading summary of a short review article on cosmic rays to become familiar with reading scientific articles.

Gain essential knowledge of the mechanisms of high-energy particle radiation in astrophysical media, including synchrotron radiation, Bremsstrahlung, inverse Compton scattering, and pi-meson production. These processes will be presented in lectures, but the course will focus on applying this knowledge to problem-solving.

Required prerequisites*:

Fluid mechanics, electromagnetism, special relativity.

Recommended prerequisites:

Plasma physics, Hamiltonian dynamics, analytical mechanics, magnetohydrodynamics.

CCI 100%: Written exam with reference materials (3 hours) + Book report to be submitted. The final grade will be the higher of the exam score and the weighted average of the exam score and the book report.

^First series of lessons:

- A Review of Cosmic Radiation.

- Motion of a charged particle in a uniform magnetic field: Larmor motion, effect of an electric field, drift of the guide center caused by an external force perpendicular to the magnetic field, drift of the guide center caused by a magnetic field gradient: magnetic moment of the particle. The first adiabatic invariant of motion in a non-uniform magnetic field and the magnetic mirror.

- Derivation of the Vlasov equation based on Klimontovich; the non-relativistic and relativistic Vlasov equations; the Landau effect; an introduction to the Fokker-Planck equation

- Derivation of the equations of ideal MHD from the Vlasov equations, single- and two-fluid equations, and the generalized Ohm’s law; Alfvén’s theorem.

- Magnetic reconnection, the Sweet-Parker model, and a few words about Petschek

- Hillas' confinement formula, second- and first-order Fermi acceleration processes (case of a shock wave).

- The quasi-linear theory of cosmic-ray transport.

^2nd series of classes:

- Radiation from accelerated charges: classical electrodynamics, relativistic generalization

- Bremsstrahlung emission

- Synchrotron radiation

- Applications: cosmic electrons

- Quantum processes: inverse Compton scattering, hadronic emission

- Applications: supernova remnant