EGU21-2032
https://doi.org/10.5194/egusphere-egu21-2032
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Higher-Order Statistics in Compressive Solar Wind Plasma Turbulence: High-Resolution Density Observations From the Magnetospheric MultiScale Mission

Owen Roberts1, Jessica Thwaites1,2, Luca Sorriso-Valvo3,4, Rumi Nakamura1, and Zoltan Voros1,5
Owen Roberts et al.
  • 1Austrian Academy of Sciences, Space Research Institute, Graz, Austria (o.wyn.roberts@gmail.com)
  • 2University of Wisconsin-Madison, Madison, WI, United States
  • 3Swedish Institute of Space Physics, SE-751 21 Uppsala, Sweden
  • 4Istituto per la Scienza e Tecnologia dei Plasmi (ISTP), Consiglio Nazionale delle Ricerche, Via Amendola 122/D, 70126 Bari, Italy
  • 5Geodetic and Geophysical Institute, Research Centre for Astronomy and Earth Sciences (RCAES), Sopron, Hungary

Turbulent density fluctuations are investigated in the solar wind at sub-ion scales using calibrated spacecraft potential. The measurement technique using the spacecraft potential allows for a much higher time resolution and sensitivity when compared to direct measurements using plasma instruments. Using this novel method, density fluctuations can be measured with unprecedentedly high time resolutions for in situ measurements of solar wind plasma at 1 a.u. By investigating 1 h of high-time resolution data, the scale dependant kurtosis is calculated by varying the time lag τ to calculate increments between observations. The scale-dependent kurtosis is found to increase towards ion scales but then plateaus and remains fairly constant through the sub-ion range in a similar fashion to magnetic field measurements. The sub-ion range is also found to exhibit self-similar monofractal behavior contrasting sharply with the multi-fractal behavior at large scales. The scale-dependent kurtosis is also calculated using increments between two different spacecraft. When the time lags are converted using the ion bulk velocity to a comparable spatial lag, a discrepancy is observed between the two measurement techniques. Several different possibilities are discussed including a breakdown of Taylor’s hypothesis, high-frequency plasma waves, or intrinsic differences between sampling directions.

How to cite: Roberts, O., Thwaites, J., Sorriso-Valvo, L., Nakamura, R., and Voros, Z.: Higher-Order Statistics in Compressive Solar Wind Plasma Turbulence: High-Resolution Density Observations From the Magnetospheric MultiScale Mission, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2032, https://doi.org/10.5194/egusphere-egu21-2032, 2021.

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