Intermittency of Magnetic Discontinuities in the Near-Sun Solar Wind Turbulence

Abstract

Abstract The intermittency domain is in the magnetohydrodynamic inertial range but just above the dissipation range and contains the intermittent structures that influence the spectral index. However, the nature of these structures is still under debate and how they affect the higher-order scaling behavior in the near-Sun solar wind turbulence remains to be investigated. Here we use the magnetic field data measured by Parker Solar Probe in the near-Sun solar wind. We identify the intermittency by partial variance of increments method and conduct the multiorder structure functions analyses in the intermittency domain before and after removing the intermittency. We also perform for the first time the scaling analyses on the fluctuations of magnetic field direction given by the rotational angle <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>θ</mml:mi> <mml:mo>=</mml:mo> <mml:msup> <mml:mrow> <mml:mi>cos</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">B</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo>·</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">B</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:mo stretchy="false">∣</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">B</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">∣</mml:mo> <mml:mo stretchy="false">∣</mml:mo> <mml:msub> <mml:mrow> <mml:mi mathvariant="bold-italic">B</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo stretchy="false">∣</mml:mo> </mml:math> , in which B 1 and B 2 are the magnetic fields measured at two instants. We find that the multifractal scaling of the magnetic field could be predicted by the log-Poisson intermittency model with 2D sheetlike structures and a simple Kolmogorov −5/3 monoscaling recovers after the removal of the intermittency. We also find a similar behavior for the scalings of θ , suggesting that magnetic discontinuities are involved in the energy transfer process of solar wind turbulence.