Gary Zank Adriaan van Ballegooijen Lecture

Adriaan van Ballegooijen Lecture: The heating of the solar corona and acceleration of the solar wind: Insights, theory, and modeling
The problem is easily stated and yet has endured for longer than the space age: the surface temperature of the Sun is a mere 6,500 degrees Kelvin yet the temperature of the solar corona exceeds 1 million degrees, hot enough to create a supersonically expanding wind that fills interplanetary space. What heats the solar corona? Fifty years after the discovery of the solar wind and the beginning of the space age, this remains the most outstanding unanswered question in space physics. This is also one of the questions that Aad van Ballegooijen focused on for much of his career, obtaining a series of seminal results that illuminated our understanding of the problem and laying much of the groundwork for solving this challenging question. NASA’s Parker Solar Probe and ESA’s Solar Orbiter spacecraft are making in situ and remote measurements of the young solar wind plasma and magnetic fields in attempting to answer the question of coronal heating and solar wind acceleration. An emerging consensus is that the solar corona is heated via the transport and dissipation of low-frequency magnetohydrodynamic turbulence. This presentation will review relevant Parker Solar Probe and Solar Orbiter observations in the context of current solar turbulence theory and modeling to show that we may be arriving at a solution to the 50-year question of the origin of the supersonic solar wind.