Anisotropic nonperturbative zero modes for passively advected magnetic fields.

Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics · 1999 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 4020

Study snapshot

PublicationPhysical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics · 1999

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

An analytic assessment of the role of anisotropic corrections to the isotropic anomalous scaling exponents is given for the d-dimensional kinematic magnetohydrodynamics problem in the presence of a mean magnetic field. The velocity advecting the magnetic field changes very rapidly in time and scales with a positive exponent xi. Inertial-range anisotropic contributions to the scaling exponents, zeta(j), of second-order magnetic correlations are associated with zero modes and have been calculated nonperturbatively. For d=3, the limit xi-->0 yields zeta(j)=j-2+xi(2j(3)+j(2)-5j-4)/[2(4j(2)-1)], where j (j>or=2) is the order in the Legendre polynomial decomposition applied to correlation functions. Conjectures on the fact that anisotropic components cannot change the isotropic threshold to the dynamo effect are also made.

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Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 78% · Peer reviewed: yes

Main findings

Provides an analytic, nonperturbative calculation of inertial-range anisotropic contributions (zero modes) to anomalous scaling exponents zeta(j) for second-order magnetic correlations in a d-dimensional kinematic magnetohydrodynamics problem with a mean magnetic field and rapidly time-varying advecting velocity. For d=3 and xi→0, an explicit expression for zeta(j) is given, and conjectures are made that anisotropic components cannot change the isotropic threshold for the dynamo effect.

Limitations

The abstract describes a theoretical/analytic physics study and does not report biological, health, or EMF exposure outcomes.
Conjectures regarding the dynamo threshold are mentioned without details on validation in the abstract.

View raw extracted JSON

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  "outcomes": [],
  "main_findings": "Provides an analytic, nonperturbative calculation of inertial-range anisotropic contributions (zero modes) to anomalous scaling exponents zeta(j) for second-order magnetic correlations in a d-dimensional kinematic magnetohydrodynamics problem with a mean magnetic field and rapidly time-varying advecting velocity. For d=3 and xi→0, an explicit expression for zeta(j) is given, and conjectures are made that anisotropic components cannot change the isotropic threshold for the dynamo effect.",
  "effect_direction": "unclear",
  "limitations": [
    "The abstract describes a theoretical/analytic physics study and does not report biological, health, or EMF exposure outcomes.",
    "Conjectures regarding the dynamo threshold are mentioned without details on validation in the abstract."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "kinematic magnetohydrodynamics",
    "mean magnetic field",
    "anisotropy",
    "anomalous scaling exponents",
    "zero modes",
    "inertial range",
    "Legendre polynomial decomposition",
    "dynamo effect"
  ],
  "suggested_hubs": []
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Identifiers and source

DOI: 10.1103/physreve.60.r3483
PubMed: 11970263

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