DETECTION OF NEGATIVE EFFECTIVE MAGNETIC PRESSURE INSTABILITY IN TURBULENCE SIMULATIONS

Journal Article · Thu Oct 20 04:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/740/2/L50· OSTI ID:21565366

Brandenburg, Axel; Kemel, Koen; Kleeorin, Nathan; Mitra, Dhrubaditya; Rogachevskii, Igor ^[1]

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1. NORDITA, AlbaNova University Center, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

We present the first numerical demonstration of the negative effective magnetic pressure instability in direct numerical simulations of stably stratified, externally forced, isothermal hydromagnetic turbulence in the regime of large plasma beta. By the action of this instability, initially uniform horizontal magnetic field forms flux concentrations whose scale is large compared to the turbulent scale. We further show that the magnetic energy of these large-scale structures is only weakly dependent on the magnetic Reynolds number. Our results support earlier mean-field calculations and analytic work that identified this instability. Applications to the formation of active regions in the Sun are discussed.

• OSTI ID: 21565366
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 740; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPUTERIZED SIMULATION
DETECTION
DIMENSIONLESS NUMBERS
FLUID MECHANICS
HYDRODYNAMICS
INSTABILITY
MAGNETIC FIELDS
MAGNETIC REYNOLDS NUMBER
MAGNETOHYDRODYNAMICS
MAIN SEQUENCE STARS
MEAN-FIELD THEORY
MECHANICS
REYNOLDS NUMBER
SIMULATION
SOLAR ACTIVITY
STARS
STARSPOTS
STELLAR ACTIVITY
SUN
SUNSPOTS
TURBULENCE