Figure 1
Illustration: NASA/SOHO/Dana Berry, Allied Signal Max Q digital animation group.

Figure 1: (a) Charged particles (red and green) emitted from the sun form an energetic solar wind. These particles spiral around the sun’s magnetic field lines (white) at the cyclotron frequency, while the field lines oscillate in the form of outwardly propagating Alfvén waves. (b) When the cyclotron frequency of the particles matches the Alfvén wave frequency, the particles absorb energy, giving them a boost.