Multifractal structure of the interplanetary magnetic field: Voyager 2 observations near 25 AU, 1987 - 1988

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Geophysical Research Letters (American Geophysical Union); (United States)

DOI:https://doi.org/10.1029/90GL02596· OSTI ID:5182344

Burlaga, L F ^[1]

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1. NASA/Goddard Space Flight Center, Wallops Island, VA (United States)

This paper analyzes the large-scale fluctuations of the interplanetary magnetic field strength observed by Voyager 2 from 23.3 AU to 27.8 AU during the period from day 190, 1987 to day 345, 1988. The q-th moments of B{sub {tau}} show scaling behavior in the range of scales from 16 hours to 21 days for {minus}10 {le} q {le} 10, i.e., {approximately} {tau}{sup s(q)} in this range. s(q) is approximately a quadratic function of q for {minus}4 {le} q {le} 4, as one expects for a distribution that is approximately lognormal, but the higher moments diverge from those of a lognormal distribution. The function D{sub q}(q) = 1 + s(q)/(q {minus} 1) has the form that is characteristic of multifractals. For a multifractal magnetic field, the moments of the field should scale as {tau}{sup {alpha}} on a set with fractal dimension f({alpha}), where {alpha} has a continuum of values over some limited range. For the large-scale magnetic field fluctuations, the function f({alpha}) computed from D{sub q}(q) is approximately a fourth order polynomial for {minus}10 {le} q {le} 10, and positive values of f({alpha}) occur for 0.8 {le} {alpha} {le} 1.2. The multifractional character of the magnetic field strength fluctuations generalizes the concept that the magnetic field is organized into interaction regions (regions in which the magnetic field strength and pressure are higher than average for several hours) and rarefaction regions (regions in which the magnetic field strength and pressure are lower than average). Near solar maximum the interaction regions in the distant heliosphere might be viewed as cluster of strong disturbed fields with considerable fine structure on various scales.

• OSTI ID: 5182344
• Journal Information: Geophysical Research Letters (American Geophysical Union); (United States), Vol. 18:1; ISSN 0094-8276
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
INTERPLANETARY MAGNETIC FIELDS
FLUCTUATIONS
DATA ANALYSIS
FRACTALS
HELIOSPHERE
MATHEMATICAL MODELS
SUN
SYMMETRY
VARIATIONS
VOYAGER SPACE PROBES
ATMOSPHERES
MAGNETIC FIELDS
MAIN SEQUENCE STARS
SOLAR ATMOSPHERE
SPACE VEHICLES
STARS
VEHICLES
640107* - Astrophysics & Cosmology- Planetary Phenomena