Solar Physics

A comprehensive graduate-level course on solar physics—from the thermonuclear core through the magnetically structured atmosphere to the heliosphere and space weather.

Course Overview

The Sun is the only star we can resolve in detail, making solar physics a unique laboratory for astrophysics, plasma physics, and magnetohydrodynamics. This course develops the physical foundations of solar structure, energy generation, oscillations, atmospheric layers, magnetic activity, and the solar-terrestrial connection.

What You'll Learn

  • • Stellar structure equations and the Standard Solar Model
  • • Nuclear reaction chains (pp, CNO) and energy transport
  • • Helioseismology: probing the interior with sound waves
  • • Solar neutrino physics and oscillation experiments
  • • Photospheric, chromospheric, and coronal physics
  • • Parker solar wind theory and MHD wind models
  • • Magnetic fields, dynamo theory, and the solar cycle
  • • Flares, CMEs, and space weather forecasting

Prerequisites

  • • Classical mechanics and thermodynamics
  • • Electrodynamics (Maxwell's equations)
  • • Introductory quantum mechanics
  • • Ordinary and partial differential equations
  • • Basic statistical mechanics
  • • Introductory astrophysics (helpful)

4 major parts | 16 chapters | Graduate level | Full derivations & simulations

Governing Equations of Solar Physics

Hydrostatic Equilibrium

The balance between gravitational compression and pressure gradient that supports the Sun:

$$\frac{dP}{dr} = -\frac{G M(r) \rho(r)}{r^2}$$

Radiative Energy Transport

The temperature gradient in the radiative zone, determined by photon diffusion through opaque matter:

$$\frac{dT}{dr} = -\frac{3 \kappa \rho L(r)}{16 \pi a c T^3 r^2}$$

Parker Solar Wind Equation

The critical-point equation for the isothermal solar wind, yielding the transonic solution:

$$\left(v - \frac{c_s^2}{v}\right)\frac{dv}{dr} = \frac{2c_s^2}{r} - \frac{GM_\odot}{r^2}$$

Magnetic Induction Equation

The evolution equation for magnetic fields in a conducting plasma, central to dynamo theory:

$$\frac{\partial \mathbf{B}}{\partial t} = \nabla \times (\mathbf{v} \times \mathbf{B}) + \eta \nabla^2 \mathbf{B}$$

Sweet-Parker Reconnection Rate

The rate of magnetic reconnection in a resistive current sheet, governing energy release in solar flares:

$$\frac{v_{\text{in}}}{v_A} = \frac{1}{\sqrt{R_m}} = \frac{1}{\sqrt{L v_A / \eta}}$$

Course Structure

🔥

Part I: Solar Interior

Stellar structure equations, the Standard Solar Model, nuclear fusion via the pp chain and CNO cycle, helioseismology (p-modes, g-modes, inversions), and the solar neutrino problem and its resolution through neutrino oscillations.

4 chapters
🌅

Part II: Solar Atmosphere

The photosphere (limb darkening, granulation, Fraunhofer lines), chromosphere (heating, spicules, Saha equation), corona (million-degree mystery, scaling laws, Alfven waves), and the Parker solar wind from first principles.

4 chapters
🧲

Part III: Solar Magnetic Activity

Zeeman effect and magnetograph measurements, the solar dynamo and mean-field electrodynamics, sunspot structure and the 11/22-year cycle, and magnetic reconnection theory powering solar flares.

4 chapters
🌍

Part IV: Space Weather

Coronal mass ejections and flux rope models, solar energetic particle acceleration, geomagnetic storms and indices (Dst, Kp), the Parker spiral, magnetopause standoff distance, and the Dungey reconnection cycle.

4 chapters

Primary References

E.R. Priest

Magnetohydrodynamics of the Sun (Cambridge, 2014)

Definitive treatment of solar MHD: magnetic field topology, reconnection theory, coronal heating, flares, and CMEs.

M.J. Aschwanden

Physics of the Solar Corona (Springer, 2005)

Comprehensive coverage of coronal observations and theory: EUV/X-ray imaging, loop physics, flare energetics, and particle acceleration.

M. Stix

The Sun: An Introduction (Springer, 2nd ed., 2002)

Classic solar physics textbook covering interior structure, oscillations, atmosphere, magnetic fields, and activity cycle.

P.V. Foukal

Solar Astrophysics (Wiley, 3rd ed., 2013)

Modern treatment emphasizing observations: radiative transfer, spectroscopy, convection, and the solar-stellar connection.

Related Courses

Plasma Physics

MHD, kinetic theory, and waves—the language of solar physics

Astrophysics

Stellar structure, nucleosynthesis, and radiative transfer fundamentals

Particle Physics

Neutrino physics, weak interactions, and oscillation phenomenology

Earth Sciences

Magnetosphere, geomagnetic field, and space weather impacts

Begin Course: Solar Interior →

Start with the structure of the Sun