How can the temperature of the Sun's atmosphere reach up to one million degrees, while that of the surface of the star is about 6000°C? By simulating the evolution of part of the Sun's interior and exterior, researchers from the Centre for Theoretical Physics (CNRS/Polytechnic School) and the Astrophysics, Instrumentation and Modelling Laboratory (CNRS/CEA/Paris Diderot University) have identified the mechanisms that provide energy capable of heating the solar atmosphere. A layer below the Sun's surface, which behaves like a boiling pot, would create a small-scale magnetic field as an energy reserve that, once out of the star, would heat successive layers of the solar atmosphere via networks of magnetic roots and branches, such as a mangrove. This atmospheric heating, involved in the creation of the solar wind that fills the heliosphere, would affect many other stars. This result was published in the journal Nature on 11 June 2015.