Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The timestep constraint in solving the gravitational wave equations sourced by hydromagnetic turbulence
Stockholm University, Nordic Institute for Theoretical Physics (Nordita). Stockholm University, Faculty of Science, Department of Astronomy. University of Colorado, USA; Carnegie Mellon Universiy, USA.ORCID iD: 0000-0002-7304-021X
Show others and affiliations
Number of Authors: 52019 (English)In: Geophysical and Astrophysical Fluid Dynamics, ISSN 0309-1929, E-ISSN 1029-0419Article in journal (Refereed) Epub ahead of print
Abstract [en]

Hydromagnetic turbulence produced during phase transitions in the early universe can be a powerful source of stochastic gravitational waves (GWs). GWs can be modelled by the linearised spatial part of the Einstein equations sourced by the Reynolds and Maxwell stresses. We have implemented two different GW solvers into the Pencil Code - a code which uses a third order timestep and sixth order finite differences. Using direct numerical integration of the GW equations, we study the appearance of a numerical degradation of the GW amplitude at the highest wavenumbers, which depends on the length of the timestep - even when the Courant-Friedrichs-Lewy condition is ten times below the stability limit. This degradation leads to a numerical error, which is found to scale with the third power of the timestep. A similar degradation is not seen in the magnetic and velocity fields. To mitigate numerical degradation effects, we alternatively use the exact solution of the GW equations under the assumption that the source is constant between subsequent timesteps. This allows us to use a much longer timestep, which cuts the computational cost by a factor of about ten.

Place, publisher, year, edition, pages
2019.
Keywords [en]
Gravitational waves, early universe, aeroacoustics, turbulence
National Category
Mathematics Earth and Related Environmental Sciences Physical Sciences
Identifiers
URN: urn:nbn:se:su:diva-173123DOI: 10.1080/03091929.2019.1653460ISI: 000482718900001OAI: oai:DiVA.org:su-173123DiVA, id: diva2:1359258
Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-10-08Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Search in DiVA

By author/editor
Brandenburg, Axel
By organisation
Nordic Institute for Theoretical Physics (Nordita)Department of Astronomy
In the same journal
Geophysical and Astrophysical Fluid Dynamics
MathematicsEarth and Related Environmental SciencesPhysical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 1 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf