Helicity conservation laws for fluids and plasmas. [Of astrophysical systems]

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/165447· OSTI ID:5967851

Bekenstein, J D

Helicity conservation laws in fluid dynamics and magnetohydrodynamics are studied. The rate of fluid helicity dissipation in nonisentropic flow is derived, and the derivation is generalized, introducing the concept of chirality and reinterpreting the Ertel-Katz law as one of a family of laws dictating the variation of the rate of dissipation of some helicity along streamlines. Woltjer's two helicity conservation laws in MHD are reviewed, and the covariant derivation of the second is given. The two Oron helicities are introduced, their conserved character is established, and a type B law arising from the second Oron helicity's conservation is proved. Departures from perfect MHD are addressed, estimating the magnetic helicity (MH) dissipation in magnetized fluids with finite conductivity and deriving a type-B law for the MH dissipation rate in a particularly simple kind of imperfect MHD flow. An Ertel-Katz type law is derived for poorly conducting magnetized fluids. 25 references.

• Research Organization: Negev Univ., Beersheba, Israel
• OSTI ID: 5967851
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 319; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640100* -- Astrophysics & Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASTROPHYSICS
CONSERVATION LAWS
COSMIC RADIO SOURCES
FLUID MECHANICS
HELMHOLTZ INSTABILITY
HYDRODYNAMICS
INSTABILITY
MAGNETOHYDRODYNAMICS
MECHANICS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
PROTOSTARS
PULSARS