Lecture

Astrophysics: Solar Physics Overview

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In course

PHYS-424: Plasma II

This course completes the knowledge in plasma physics that students have acquired in the previous two courses, with a discussion of different applications, in the fields of magnetic confinement and controlled fusion, astrophysical and space plasmas, and so ...

Description

This lecture introduces solar physics, covering the convective and radiative zones of the Sun, its nuclear energy source, magnetic field structure, and the proton-proton chain reaction. It explores the properties of the Sun, such as its distance, mass, radius, luminosity, and elemental abundances. The lecture delves into the luminosity-mass dependence for main sequence stars, hydrostatic equilibrium, and the temperature profile in the Sun's interior. It discusses energy transport mechanisms, opacity in plasmas, and the escape of photons. The lecture also touches on convection, sunspots, the solar cycle, and the global magnetic field structure of the Sun.

Instructor

Holger Reimerdes

Teaching & PhD PhD Students Martim Zurita, Marta Pedrini, Benjamin Yong Kwak Brown, Pierre Louis Sintre, Massimo Carpita, Richard Alexander David Ducker, Giuseppe Iunior Drago Past EPFL PhD Students Mirko Wensing, Claudia Colandrea, Guang-Yu Sun Past EPFL PhD Students as codirector Gustavo Paganini Canal, Joyeeta Sinha, Roberto Maurizio Courses Control and Operation of Tokamaks PHYS-748 This course treats the main issues in operation and control of a tokamak. Control-oriented models are de

Official source

Ontological neighbourhood

Astronomy

Astrophysics: Stellar astronomy

Physics

Plasma physics: Space-plasma physics

Related concepts (32)

Convection zone

A convection zone, convective zone or convective region of a star is a layer which is unstable due to convection. Energy is primarily or partially transported by convection in such a region. In a radiation zone, energy is transported by radiation and conduction. Stellar convection consists of mass movement of plasma within the star which usually forms a circular convection current with the heated plasma ascending and the cooled plasma descending. The Schwarzschild criterion expresses the conditions under which a region of a star is unstable to convection.

Radiation zone

A radiation zone, or radiative region is a layer of a star's interior where energy is primarily transported toward the exterior by means of radiative diffusion and thermal conduction, rather than by convection. Energy travels through the radiation zone in the form of electromagnetic radiation as photons. Matter in a radiation zone is so dense that photons can travel only a short distance before they are absorbed or scattered by another particle, gradually shifting to longer wavelength as they do so.

Main sequence

In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or dwarf stars. These are the most numerous true stars in the universe and include the Sun. After condensation and ignition of a star, it generates thermal energy in its dense core region through nuclear fusion of hydrogen into helium.

Solar cycle

The solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a nearly periodic 11-year change in the Sun's activity measured in terms of variations in the number of observed sunspots on the Sun's surface. Over the period of a solar cycle, levels of solar radiation and ejection of solar material, the number and size of sunspots, solar flares, and coronal loops all exhibit a synchronized fluctuation from a period of minimum activity to a period of a maximum activity back to a period of minimum activity.

G-type main-sequence star

A G-type main-sequence star (spectral type: G-V), also often, and imprecisely called a yellow dwarf, or G star, is a main-sequence star (luminosity class V) of spectral type G. Such a star has about 0.9 to 1.1 solar masses and an effective temperature between about 5,300 and 6,000 K. Like other main-sequence stars, a G-type main-sequence star converts the element hydrogen to helium in its core by means of nuclear fusion, but can also fuse helium when hydrogen runs out.

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