Intermittency in Solar Wind Plasma: Finding the Missing Dissipation

Speaker: Kathryn Ledbetter

Time: 12:00pm March 15 2017

Location: SUSB Havasu Conference Room (3004)

Abstract

The Sun is constantly emitting streams of plasma into the Solar System, 'blowing a bubble' in the interstellar medium and creating the space weather environment we live in. This plasma, termed the solar wind, flies through space at 400-600 km/s on a calm day, but is generally dilute: only ~10 protons/cm^3. Observations of the solar wind raise a perplexing problem: as the plasma streams outwards from its origin in the solar corona (temperature around 3 million Kelvin), how is energy dissipated if the mean free path of particles is on the order of 1 AU? Analyses including kurtosis and partial variance of increments revealed that the solar wind is extremely 'bursty,' suggesting that structures exist in the plasma which are intermittent in space and time. Turbulence leading to magnetic reconnection and local heating could explain both intermittent structures and the 'missing' dissipation.