---
abstract: 'The Sun’s internal structure and dynamics can be studied with helioseismology, which uses the Sun’s natural acoustic oscillations to build up a profile of the solar interior. We discuss how solar acoustic oscillations are affected by the Sun’s magnetic field. Careful observations of these effects can be inverted to determine the variations in the structure and dynamics of the Sun’s interior as the solar cycle progresses. Observed variations in the structure and dynamics can then be used to inform models of the solar dynamo, which are crucial to our understanding of how the Sun’s magnetic field is generated and maintained.'
author:
- 'A.-M. Broomhall, P. Chatterjee, R. Howe, A.A. Norton, M.J. Thompson'
bibliography:
- 'ISSI\_helio\_chapter.bib'
title: 'The Sun’s interior structure and dynamics, and the solar cycle'
---

Introduction to helioseismology {#section[intro]}
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Helioseismology is the study of the solar interior using observations of waves that propagate within the Sun. The Sun’s natural acoustic resonant oscillations are known as solar p modes. The p stands for pressure as the main restoring force is a pressure differential. At any one time thousands of acoustic oscillations are traveling throughout the solar interior. Each individual solar p mode is trapped in a 