Universal properties of mirror mode turbulence in the Earth's magnetosheath

We use more than 7 years of Time History of Events and Macroscale Interactions during Substorms observations to quantify the non‐Gaussian properties associated with mirror mode turbulence in the Earth's magnetosheath. We find that non‐Gaussian statistics of mirror modes lead to the parabolic collapse of kurtosis as the square of the skewness (K = aS2+B with a ∼ 1.3 and b ∼− 1). The parabolic scaling is a global constraint for the magnetosheath and is dictated by kinetic processes. This parabolic scaling is qualitatively independent of the distance to the magnetopause or bow shock, which implies that, even though the bow shock is driving the mirror mode instability, the dynamical evolution of mirror structures is independent of the source region and due to local processes. The parabolic relationship and coefficients between kurtosis and skewness for mirror modes in the Earth's magnetosheath are also similar to those found in a wide range of geophysical and laboratory turbulent environments, providing further evidence that turbulent systems dominated by non‐Gaussian fluctuations hold universal statistical properties. Key Points Mirror modes in magnetosheath result in parabolic scaling of kurtosis‐skewness Parabolic K‐S collapse of mirror structures is a global magnetosheath constraint Parabolic relationship for mirror modes underlies universal turbulent properties