Mikael Mortensen


4DSpace

In the strategic research initiative 4DSpace we study instabilities and turbulence in the polar ionosphere with an integrated, multi-scale 4D (3D in space and time) experimental, theoretical, and modelling approach.

Two of my PhD students Diako Darian and Sigvald Marholm are both working under the 4DSpace umbrella, that alltogether count approximately 40 people. We are focusing on developing unstructured Particle In Cell (PIC) codes with finite element and Lagrangian particle methods, within the FEniCS framework. See Marholm et al. [1] and the Particles in UNstructured Cells code PUNC.

In the paper by Darian et al. [2] we use PIC simulations of a sounding rocket in ionospheric plasma to investigate effects of magnetic field on the wake formation and rocket potential. In the paper by Miloch et al. [3] we study dynamic ion shadows behind finite-sized objects in collisionless magnetized plasma flows.

Darian and Mortensen [4] have implemented a spectral MagnetoHydroDynamics solver with the Boussinesq approximation for variable densities within the spectralDNS framework, and use it to study Kelvin-Helmholtz instabilities in stratified and unstratified shear layers.

Miloch, Darian and Mortensen [5] study the wake potential of a dust particle in magnetised plasmas.

References

  1. S. Marholm, D. Darian, M. Mortensen, R. Marchand and W. J. Miloch. A Novel Method for Circuits of Perfect Electric Conductors in Unstructured Particle–In–Cell Plasma–Object Interaction Simulations, Submitted to journal for publication, 2018, http://folk.uio.no/mikaem/preprints/marholm2018.pdf.
  2. D. Darian, S. Marholm, J. J. P. Paulsson, Y. Miyake, H. Usui, M. Mortensen and W. J. Miloch. Numerical Simulations of a Sounding Rocket in Ionospheric Plasma: Effects of Magnetic Field on the Wake Formation and Rocket Potential., Journal of Geophysical Research: Space Physics, pp. n/a-n/a, doi: 10.1002/2017JA024284, 2017.
  3. W. J. Miloch, H. Jung, F. Greiner, A. Piel, D. Darian and M. Mortensen. Dynamic Ion Shadows Behind Finite-Sized Objects in Collisionless Magnetized Plasma Flows, Accepted for publication in The New Journal of Physics, 2018, http://iopscience.iop.org/article/10.1088/1367-2630/aad066.
  4. D. Darian and M. Mortensen. A Pseudo-Spectral Study of Kelvin-Helmholtz Instability, Proceedings of the eighth national conference on computational mechanics, MekIT'15, 2015, https://www.researchgate.net/profile/Mikael_Mortensen/publication/294088678_A_PSEUDO-SPECTRAL_STUDY_OF_KELVIN-HELMHOLTZ_INSTABILITY/links/56bdf42e08ae44da37f883d8.pdf.
  5. W. J. Miloch, D. Darian and M. Mortensen. Wake Potential of a Dust Particle in Magnetised Plasmas, Physica Scripta, 92(11), pp. 114006, 2017, http://stacks.iop.org/1402-4896/92/i=11/a=114006.