Kinetic-scale Spectral Features of Cross Helicity and Residual Energy in the Inner Heliosphere

In this work, we present the first results from the flux angle (FA) operation mode of the Faraday Cup instrument on board the Parker Solar Probe (PSP). The FA mode allows rapid measurements of phase space density fluctuations close to the peak of the proton velocity distribution function with a cadence of 293 Hz. This approach provides an invaluable tool for understanding kinetic-scale turbulence in the solar wind and solar corona. We describe a technique to convert the phase space density fluctuations into vector velocity components and compute several turbulence parameters, such as spectral index, residual energy, and cross helicity during two intervals when the FA mode was used in PSP’s first encounter at 0.174 au distance from the Sun.

[1]  D. Stansby,et al.  Highly structured slow solar wind emerging from an equatorial coronal hole , 2019, Nature.

[2]  N. Pogorelov,et al.  Alfvénic velocity spikes and rotational flows in the near-Sun solar wind , 2019, Nature.

[3]  David E. Trilling,et al.  The Astrophysical Journal Supplement Series , 2019 .

[4]  C. Russell,et al.  Kinetic Range Spectral Features of Cross Helicity Using the Magnetospheric Multiscale Spacecraft. , 2018, Physical review letters.

[5]  T. Horbury,et al.  Short, large-amplitude speed enhancements in the near-Sunfast solar wind , 2018 .

[6]  S. Bale,et al.  Impact of Residual Energy on Solar Wind Turbulent Spectra , 2018, The Astrophysical Journal.

[7]  J. Kasper,et al.  Magnetic Reconnection May Control the Ion-scale Spectral Break of Solar Wind Turbulence , 2018, 1803.00065.

[8]  R. Grappin,et al.  3D Anisotropy of Solar Wind Turbulence, Tubes, or Ribbons? , 2018, 1802.09837.

[9]  J. Kasper,et al.  Nature of Stochastic Ion Heating in the Solar Wind: Testing the Dependence on Plasma Beta and Turbulence Amplitude , 2017, 1711.01508.

[10]  L. Přech,et al.  Variety of shapes of solar wind ion flux spectra: Spektr-R measurements , 2017, Journal of Plasma Physics.

[11]  A. Schekochihin,et al.  Disruption of Alfvénic turbulence by magnetic reconnection in a collisionless plasma , 2017, Journal of Plasma Physics.

[12]  S. Boldyrev,et al.  Collisionless Reconnection in Magnetohydrodynamic and Kinetic Turbulence , 2017, 1707.05899.

[13]  Christopher H. K. Chen,et al.  Electric and magnetic spectra from MHD to electron scales in the magnetosheath , 2017 .

[14]  S. Boldyrev,et al.  Nature of Kinetic Scale Turbulence in the Earth's Magnetosheath , 2016, 1705.08558.

[15]  M. Lockwood,et al.  The Solar Probe Plus Mission: Humanity’s First Visit to Our Star , 2016 .

[16]  Christopher H. K. Chen,et al.  POWER SPECTRAL DENSITY OF FLUCTUATIONS OF BULK AND THERMAL SPEEDS IN THE SOLAR WIND , 2016 .

[17]  D. Werthimer,et al.  The FIELDS Instrument Suite for Solar Probe Plus , 2016, Space Science Reviews.

[18]  John W. Belcher,et al.  Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus , 2015 .

[19]  T. Horbury,et al.  CORRELATIONS AT LARGE SCALES AND THE ONSET OF TURBULENCE IN THE FAST SOLAR WIND , 2013, 1312.4585.

[20]  S. Boldyrev,et al.  Nature of subproton scale turbulence in the solar wind. , 2013, Physical review letters.

[21]  S. Bale,et al.  RESIDUAL ENERGY SPECTRUM OF SOLAR WIND TURBULENCE , 2013, 1304.7818.

[22]  L. Přech,et al.  Fast Solar Wind Monitor (BMSW): Description and First Results , 2013 .

[23]  L. Přech,et al.  Ion kinetic scale in the solar wind observed. , 2013, Physical review letters.

[24]  J. Gosling,et al.  PULSED ALFVÉN WAVES IN THE SOLAR WIND , 2011 .

[25]  S. Boldyrev,et al.  RESIDUAL ENERGY IN MAGNETOHYDRODYNAMIC TURBULENCE , 2011, 1106.2238.

[26]  S. Boldyrev,et al.  SPECTRAL SCALING LAWS IN MAGNETOHYDRODYNAMIC TURBULENCE SIMULATIONS AND IN THE SOLAR WIND , 2011, 1106.0700.

[27]  S. Schwartz,et al.  Universality of solar-wind turbulent spectrum from MHD to electron scales. , 2009, Physical review letters.

[28]  Charles W. Smith,et al.  Statistical Analysis of the High-Frequency Spectral Break of the Solar Wind Turbulence at 1 AU , 2008 .

[29]  B. Chandran.  Strong Anisotropic MHD Turbulence with Cross Helicity , 2008, 0801.4903.

[30]  P. Mininni,et al.  Rapid alignment of velocity and magnetic field in magnetohydrodynamic turbulence. , 2007, Physical review letters.

[31]  M. Goldstein,et al.  Spectral Exponents of Kinetic and Magnetic Energy Spectra in Solar Wind Turbulence , 2007 .

[32]  W. Dorland,et al.  Kinetic and fluid turbulent cascades in magnetized weakly collisional astrophysical plasmas , 2007 .

[33]  Kathleen E. Hamilton,et al.  Dependence of the Dissipation Range Spectrum of Interplanetary Magnetic Fluctuationson the Rate of Energy Cascade , 2006 .

[34]  T. Horbury,et al.  Measurement of the electric fluctuation spectrum of magnetohydrodynamic turbulence. , 2005, Physical review letters.

[35]  S. Boldyrev.  On the Spectrum of Magnetohydrodynamic Turbulence , 2005, Physical review letters.

[36]  H. K. Wong,et al.  Observational constraints on the dynamics of the interplanetary magnetic field dissipation range , 1998 .

[37]  W. Matthaeus,et al.  Linear transport of solar wind fluctuations , 1995 .

[38]  B. Bavassano,et al.  Cross-helicity depletions in the inner heliosphere, and magnetic field and velocity fluctuation decoupling , 1993 .

[39]  B. Bavassano,et al.  Origin of low cross-helicity regions in the inner solar wind , 1991 .

[40]  E. Marsch,et al.  On the origin of solar wind MHD turbulence: Helios data revisited , 1990 .

[41]  D. A. Roberts,et al.  Origin and evolution of fluctuations in the solar wind: Helios observations and Helios-Voyager comparisons , 1987 .

[42]  William H. Matthaeus,et al.  Measurement of the rugged invariants of magnetohydrodynamic turbulence in the solar wind , 1982 .

[43]  P. Coleman.  Turbulence, viscosity, and dissipation in the solar-wind plasma , 1968 .

[44]  H. Alfvén,et al.  Existence of Electromagnetic-Hydrodynamic Waves , 1942, Nature.

[45]  Ashis Bhattacharjee,et al.  Scale‐dependent angle of alignment between velocity and magnetic field fluctuations in solar wind turbulence , 2009 .

[46]  H. Rosenbauer,et al.  On the ``inward'' component of the Alfvénic turbulence in the solar wind , 1997 .