Statistics of the interplanetary magnetic fields observed at 0.72 AU and 1 AU

This paper presents the Interplanetary Magnetic Field (IMF) observations at 0.72 AU measured by Venus Express (VEX) and 1 AU by Advanced Composition Explorer (ACE) in 2007. The distributions of daily averages of $B$ are lognormal in both locations. The multiscale structure of the magnetic field fluctuations was described by studying the increments of $B$ over a range scales from 10 min to 21.3 hours. All the Probability Distribution Functions (PDFs) can be described quantitatively by Tsallis distribution function. On the ecliptic plane from 0.72 AU to 1 AU, the entropy index q increases with distance over all scales, indicating the intermittency of turbulence is growing. The widths of the PDFs at 0.72 AU are larger than those at 1 AU at all scales, which indicating the turbulence at 0.72 AU is more intense than that at 1 AU. This helps us understand the nature and development of the magnetic field fluctuations.