STATISTICS OF DENSITY FLUCTUATIONS DURING THE TRANSITION FROM THE OUTER SOLAR CORONA TO THE INTERPLANETARY SPACE

Journal Article · Fri Nov 20 00:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/706/1/238· OSTI ID:21378208

Telloni, D; Antonucci, E ^[1]; Bruno, R; D'Amicis, R ^[2]; Carbone, V ^[3]

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1. Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Torino, Via Osservatorio 20, 10025 Pino Torinese (Italy)
2. Istituto Nazionale di Astrofisica (INAF), Istituto di fisica dello Spazio Interplanetario, Via del Fosso del Cavaliere 100, 00133 Rome (Italy)
3. Universita della Calabria, Dipartimento di fisica, Ponte P. Bucci, Cubo 31C, 87036 Rende (Italy)

This paper investigates the evolution of the plasma density fluctuations of the fast and slow solar wind from the solar corona into the interplanetary space. The study is performed by comparing the low-frequency spectra and the phase correlation of the proton density oscillations, measured in the inner heliosphere with the Helios 2 in situ instrumentation, with those due to the large-scale density perturbations observed with UVCS/SOHO in the outer corona. We find that the characteristics of density fluctuations of the fast solar wind are maintained in the transition from the outer corona to the inner heliosphere, thus suggesting a coronal imprint for the heliospheric large-scale 1/f {sup 2} noise spectrum. In contrast, a quick dynamical evolution is observed in the slow wind, which, starting from large-scale fluctuations with strong phase correlations in the outer corona, gives rise to a Kolmogorov-like spectrum and an accumulation of density structures at small scales at 0.3 AU. This can be explained in the framework of nearly incompressible turbulence.

• OSTI ID: 21378208
• Journal Information: Astrophysical Journal, Vol. 706, Issue 1; Other Information: DOI: 10.1088/0004-637X/706/1/238; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
DENSITY
FLUCTUATIONS
HELIOSPHERE
INTERPLANETARY SPACE
PERTURBATION THEORY
PLASMA DENSITY
PROTON DENSITY
SOLAR CORONA
SOLAR WIND
STATISTICS
SUN
TURBULENCE
ATMOSPHERES
MAIN SEQUENCE STARS
MATHEMATICS
PHYSICAL PROPERTIES
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SPACE
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR WINDS
VARIATIONS