Non-Gaussianity and cross-scale coupling in interplanetary magnetic field turbulence during a rope–rope magnetic reconnection event

Abstract

Abstract. In a recent paper (Chian et al., 2016) it was shown that magnetic reconnection at the interface region between two magnetic flux ropes is responsible for the genesis of interplanetary intermittent turbulence. The normalized third-order moment (skewness) and the normalized fourthorder moment (kurtosis) display a quadratic relation with a parabolic shape that is commonly observed in observational data from turbulence in fluids and plasmas, and is linked to non-Gaussian fluctuations due to coherent structures. In this paper we perform a detailed study of the relation between the skewness and the kurtosis of the modulus of the magnetic field |B| during a triple interplanetary magnetic flux rope event. In addition, we investigate the skewness-kurtosis relation of two-point differences of |B| for the same event. The parabolic relation displays scale dependence and is found to be enhanced during magnetic reconnection, rendering support for the generation of non-Gaussian coherent structures via rope-rope magnetic reconnection. Our results also indicate that a direct coupling between the scales of magnetic flux ropes and the scales within the inertial subrange occurs in the solar wind.

Objective magnetic vortex detection

“…A possible application is the reconnection of the solar emerging flux ropes with the coronal field [38]. Detection of the boundary layers in interacting magnetic flux ropes is also crucial for understanding the origin of intermittent turbulence in the solar wind, with resulting non-Gaussian statistics and cross-scale coupling [39,40]. Additionally, flux ropes are found in coronal mass ejections (CMEs), giant releases of plasma from the Sun.…”

Nonlinear dynamics in space plasma turbulence: temporal stochastic chaos

“…This relation can elucidate the universal statistical properties of intermittent turbulence. Miranda et al (2018) investigated the kurtosis-skewness relation of the triple interplanetary magnetic flux rope event studied by Chian et al (2016). Figure 20 shows the time 21.…”

Chaos, complexity, and intermittent turbulence in space plasmas

“…This relation can elucidate the universal statistical properties of intermittent turbulence. Miranda et al (2018) investigated the kurtosis-skewness relation of the triple interplanetary magnetic flux rope event studied by Chian et al (2016). Figure 8 shows the time series of two-point differences (τ = 100s) of the modulus of magnetic field measured by Cluster-1 and the corresponding skewness and kurtosis, where the five regions of 30 min each are the same as specified in Fig.…”

“…The functional relation between kurtosis and skewness for each region can be described by the quadratic equation where α and β are the coefficients that characterize a parabolic curve which can be computed by applying a least-square fit between the values of kurtosis and skewness obtained from the observational data and Eq. ( 2), following the Levenberg-Marquardt algorithm (Miranda et al 2018). A correlation index r can be computed to measure the degree of correlation between the value of observed K and the value of K obtained empirically from Eq.…”

“…9(e) with α = 1.36 , β = 0.72) due to nonlinear Alfvén waves and coherent structures such as small-scale current sheets and magnetic flux ropes related to the interplanetary rope-rope magnetic reconnection discussed in Section 3.2.1. The studies of the kurtosis-skewness relation of Vörös et al (2006) and Miranda et al (2018) show that the solar wind intermittent turbulence can be induced by cross-scale interactions.…”