Open AccessFurther evidence of wave refraction associated with extended rarefaction events in the solar wind
Author(s) -
Smith Charles W.,
Mullan Dermott J.,
Ness Norman F.
Publication year - 2004
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003ja010113
Subject(s) - physics , solar wind , rarefaction (ecology) , amplitude , refraction , astrophysics , turbulence , interplanetary magnetic field , magnetic field , computational physics , geophysics , atmospheric sciences , mechanics , optics , geology , paleontology , quantum mechanics , species richness
We examine the turbulence and low‐frequency wave properties of three extended rarefaction intervals observed by the Advanced Composition Explorer (ACE) spacecraft in 1999 and 2002 while in orbit at L 1 . The proton densities drop to values lower than 1 cm −3 and in one case reach 0.1 cm −3 . During each interval, the amplitudes of magnetic fluctuations fall to unusually low levels. Moreover, the fluctuations that are present are more Alfvénic in nature than in the typical low‐latitude wind. The constant and near average interplanetary magnetic field during these times results in elevated Alfvén speeds. We suggest that the relative isolation of the rarefaction intervals from sources of turbulence‐generating transients allows wave refraction to become a significant dynamic controlling the evolution of the magnetized plasma. We present analyses of the intervals that support the hypothesis that wave refraction explains the reduced fluctuation levels and enhanced Alfvénicity during these times.