Statistical analysis of intermittency in solar wind transients: Solar Orbiter and Parker Solar Probe observations

Intermittency is a common feature of solar wind turbulence where it presents itself as non-Gaussian fluctuations and embedded coherent structures. Small-scale magnetic field fluctuations in interplanetary coronal mass ejections (ICMEs) have a behaviour matching the presence of intermittency but properties and significance of intermittency in ICMEs are not yet known. We use data from Solar Orbiter and Parker Solar Probe to study intermittency in 49 ICMEs and the related upstream and downstream solar wind periods and sheath regions at heliospheric distances of 0.25-1 au. For comparing the different plasma environments, the gradient of kurtosis is used to measure intermittency with larger values being an indication of faster increase of kurtosis towards smaller scales and thus higher level of intermittency. Kurtosis is seen to behave similarly in all studied plasma environments, but the largest gradients are seen in the upstream solar wind at the lower end of the inertial range. The downstream solar wind, sheaths and ICMEs show similar values and behaviour for the gradient. The connection between kurtosis and common plasma parameters is studied with some differences found in different intervals but with no strong correlations.