Description of the objective:
Quantify the evolution of the turbulent spectrum with distance, heliomagnetic latitude and stream structure in the inner heliosphere.
- Determine in what conditions the radial evolution is a matter of age of turbulence or in situ heliospheric sources.
- Try to connect in situ spectrum with source spectrum at the Sun (together with sophisticated models).
- Get insight into the observed correlation between speed, temperature and fluctuations amplitude (Grappin et al., 1990) by comparing in situ properties and source region properties.