Beyond the Oberbeck–Boussinesq and long wavelength approximation

M. Held*, Matthias Wiesenberger

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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We present the first simulations of a reduced magnetized plasma model that incorporates both arbitrary wavelength polarization and non-Oberbeck–Boussinesq effects. Significant influence of these two effects on the density, electric potential and E × B vorticity and non-linear dynamics of interchange blobs are reported. Arbitrary wavelength polarization implicates so-called gyro-amplification that compared to a long wavelength approximation leads to highly amplified small-scale E × B vorticity fluctuations. These strongly increase the coherence and lifetime of blobs and alter the motion of the blobs through a slower blob-disintegration. Non-Oberbeck–Boussinesq effects incorporate plasma inertia, which substantially decreases the growth rate and linear acceleration of high amplitude blobs, while the maximum blob velocity is not affected. Finally, we generalize and numerically verify unified scaling laws for blob velocity, acceleration and growth rate that include both ion temperature and arbitrary blob amplitude dependence.
Original languageEnglish
Article number026008
JournalNuclear Fusion
Issue number2
Number of pages16
Publication statusPublished - 2023


  • Gyro-fluid
  • Gyro-kinetic
  • Boussinesq approximation
  • Long wavelenght limit
  • Finite Larmor radius effects
  • Scrape-off layer transport
  • Arbitrary wavelength polarization


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