Radial evolution of magnetic field fluctuations in an ICME sheath
- 1Department of Physics, University of Helsinki, Finland (simon.good@helsinki.fi)
- 2Space Sciences Laboratory, University of California–Berkeley, Berkeley, USA
The sheaths of compressed solar wind that precede interplanetary coronal mass ejections (ICMEs) commonly display large-amplitude magnetic field fluctuations. As ICMEs propagate radially from the Sun, the properties of these fluctuations may evolve significantly. We present a case study of an ICME sheath observed by a pair of radially aligned spacecraft at around 0.5 and 1 AU from the Sun. Radial changes in fluctuation amplitude, compressibility, inertial-range spectral slope, permutation entropy, Jensen-Shannon complexity, and planar structuring are characterised. We discuss the extent to which the observed evolution in the fluctuations is similar to that of solar wind emanating from steady sources at quiet times, how the evolution may be influenced by evolving local factors such as leading-edge shock orientation, and how the perturbed heliospheric environment associated with ICME propagation may impact the evolution more generally.
How to cite: Good, S., Ala-Lahti, M., Palmerio, E., Kilpua, E., and Osmane, A.: Radial evolution of magnetic field fluctuations in an ICME sheath, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13664, https://doi.org/10.5194/egusphere-egu2020-13664, 2020
