The Zeeman Effect

The magnetic field of the Sun can be probed in a rather precise and direct manner because in the presence of a magnetic field the energy levels of atoms (and ions and molecules) are split into more than one level. This causes spectral transition lines to also be split into more than one line, with the amount of splitting proportional to the strength of the magnetic field. This is called the Zeeman Effect, and the corresponding increase in the number of spectral lines is called Zeeman splitting. Thus, we can infer the presence of magnetic fields if we observe Zeeman splitting in the spectrum, and we can measure the strength of the field by measuring quantitatively the amount of Zeeman splitting.

The magnetic field of the Sun can be probed in a rather precise and direct manner because in the presence of a magnetic field the energy levels of atoms (and ions and molecules) are split into more than one level. This causes spectral transition lines to also be split into more than one line, with the amount of splitting proportional to the strength of the magnetic field. This is called the Zeeman Effect, and the corresponding increase in the number of spectral lines is called Zeeman splitting. Thus, we can infer the presence of magnetic fields if we observe Zeeman splitting in the spectrum, and we can measure the strength of the field by measuring quantitatively the amount of Zeeman splitting.