Studying Interstellar Turbulence Driving Scales Using the Bispectrum

Michael J. O’Brien, Blakesley Burkhart, Michael J. Shelley

Research output: Contribution to journalArticlepeer-review


We demonstrate the utility of the bispectrum, the Fourier three-point correlation function, for studying driving scales of magnetohydrodynamic (MHD) turbulence in the interstellar medium. We calculate the bispectrum by implementing a parallelized Monte Carlo direct measurement method, which we have made publicly available. In previous works, the bispectrum has been used to identify nonlinear scaling correlations and break degeneracies in lower-order statistics like the power spectrum. We find that the bicoherence, a related statistic which measures phase coupling of Fourier modes, identifies turbulence-driving scales using density and column density fields. In particular, it shows that the driving scale is phase-coupled to scales present in the turbulent cascade. We also find that the presence of an ordered magnetic field at large scales enhances phase coupling as compared to a pure hydrodynamic case. We therefore suggest the bispectrum and bicoherence as tools for searching for non-locality for wave interactions in MHD turbulence.

Original languageEnglish (US)
Article number149
JournalAstrophysical Journal
Issue number2
StatePublished - May 1 2022

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Studying Interstellar Turbulence Driving Scales Using the Bispectrum'. Together they form a unique fingerprint.

Cite this