English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Magnetic fields are important contributers to the dynamics of collapsingmolecular cloud cores, and can have a major effect on whether collapse resultsin a single protostar or fragmentation into a binary or multiple protostarsystem. New models are presented of the collapse of magnetic cloud cores usingthe adaptive mesh refinement (AMR) code Enzo2.0. The code was used to calculatethe ideal magnetohydrodynamics (MHD) of initially spherical, uniform densityand rotation clouds with density perturbations, i.e., the Boss and Bodenheimer(1979) standard isothermal test case for three dimensional (3D) hydrodynamics(HD) codes. After first verifying that Enzo reproduces the binary fragmentationexpected for the non-magnetic test case, a large set of models was computedwith varied initial magnetic field strengths and directions with respect to thecloud core axis of rotation (parallel or perpendicular), density perturbationamplitudes, and equations of state. Three significantly different outcomesresulted: (1) contraction without sustained collapse, forming a denser cloudcore, (2) collapse to form a single protostar with significant spiral arms, and(3) collapse and fragmentation into binary or multiple protostar systems, withmultiple spiral arms. Comparisons are also made with previous MHD calculationsof similar clouds with barotropic equations of state. These results for thecollapse of initially uniform density spheres illustrate the central importanceof both magnetic field direction and field strength for determining the outcomeof dynamic protostellar collapse.

Collapse and Fragmentation of Magnetic Molecular Cloud Cores with the Enzo AMR MHD Code. I. Uniform Density Sphere