Audun Theodorsen

Foto: Jonatan Ottesen/UiT

Audun Theodorsen

Intermittent fluctuations in physical systems

HOST INSTITUTE: Department of Physics and Technology (IFT), NT-fak
PERIOD: 2020-2023

This project studies the sudden and large fluctuations that appear in various physical systems, with focus on four application areas:

  • near-wall turbulence in fusion energy reactors,
  • cosmic dust in the interplanetary medium,
  • the contribution of volcanic activity to the climate system, and
  • transport of aerosol pollution in the atmosphere

Standard methods in physics often rely on investigating the consequences of small disturbances. When these methods are used to study phenomena with random and large events, the probability of damage over time, accidents and catastrophic events can be fatally underestimated. In this project, we use a statistical model which takes such large, sudden and random fluctuations into account, and allows for predicting the effect of large disturbances with much better accuracy.

Despite the large differences between these four systems, measurements from them share many statistical properties. With a common statistical modelling approach, this project will investigate important questions in all application areas:

  • How do the properties of the turbulence depend on fusion energy reactor parameters
  • How does the turbulence influence the interactions between the plasma and the wall and wall damage?
  • How is cosmic dust distributed between the sun and the earth?
  • What is the dust influx to the atmosphere of the Earth?
  • What is the global temperature response to volcanic activity?
  • What are the properties of the short-time structures in atmospheric aerosols?

In his doctoral thesis, Audun Theodorsen shows that the model is an effective tool for understanding the properties of near-wall turbulence in fusion energy reactors. The goal of this project is to develop the model as a universal tool in research of large fluctuations. The chosen application areas in sustainable energy, space- and atmosphere physics and climate research have high societal relevance.

Audun Theodorsen has a master’s degree and PhD in fusion plasma physics from UiT and is employed as a postdoctor at UiT since March 2019. During his PhD, he spent a year at the MIT Plasma Science and Fusion Center. This project is a collaboration between UiT – the Arctic University of Norway, MIT, National Oceanic and Atmospheric Administration, University of California San Diego, ETH Zurich, Sorbonne University, the Max Planck Institute for Plasma Physics, Colorado State University and the Culham Centre for Fusion Energy.

Inside of the fusion experiment JET. Source: EUROfusion
Inside of the fusion experiment JET. Source: EUROfusion
Sun-grazing comet. Source: SOHO (ESA og NASA)
Sun-grazing comet. Source: SOHO (ESA og NASA)
Mount Pinatubo eruption, 1991. Source: U.S. Geological Survey
Mount Pinatubo eruption, 1991. Source: U.S. Geological Survey