Moscow, Russian Federation
Moskva, Moscow, Russian Federation
Moscow, Russian Federation
We have analyzed spectra of fluctuations in the solar wind plasma flux and the magnetic field magnitude near the front of a fast reverse shocks, using data from the BMSW device (Bright Monitor of Solar Wind) operating on the SPEKTR-R satellite. Its time resolution made it possible to study plasma flux fluctuations up to a frequency of 16 Hz. Magnetic field data was taken mainly from the WIND satellite, for which the frequency of the fluctuations considered was up to 5.5 Hz. The slope of the spectra of the solar wind flux fluctuations on MHD scales has been shown to be close to the slope of the spectrum of magnetic field fluctuations in the disturbed region. On kinetic scales, the difference can be significant. For the region ahead of the front, the difference in the slope of the spectrum can be quite large both in the MHD and in the kinetic region. The frequency of the break of the flux spectrum ranges from 0.6 to 1.3 Hz, which corresponds to the scale of the proton inertial length. In a number of events, however, the shape of the spectrum indicates the influence of the proton gyroradius frequency, which is usually 0.05–0.15 Hz. The break in the power spectrum of magnetic field fluctuations also more often ranges from 0.7 to 1.2 Hz. In this case, the slope of the MHD part of the spectrum changes little, but in the kinetic part it increases slightly when moving to the disturbed region.
solar wind, interplanetary shocks, fluctuations
1. Bruno R., Carbone V. The solar wind as a turbulence laboratory. Living Rev. Solar Phys. 2013, vol. 10, no. 2. DOI: 10.12942/ lrsp-2013-2.
2. Howes G.G., Cowley S.C., Dorland W., Hammett G.W., Quataert E., Schekochihin A.A. A model of turbulence in magnetized plasmas: Implications for the dissipation range in the solar wind. Geophys. Res. 2008, vol. 113. DOI:https://doi.org/10.48550/arXiv.0707.3147.
3. Kolmogorov A.N. A refinement of previous hypotheses concerning the local structure of turbulence in a viscous incompressible fluid at high Reynolds number. J. Fluid Mech. 1962, vol. 13, pp. 82–85. DOI:https://doi.org/10.1017/S0022112062000518.
4. Leamon R.J., Matthaeus W.H., Smith C.W., Zank G.P., Mullan D.J., Oughton S. MHD-driven kinetic dissipation in the solar wind and corona. Astrophys. J. 2000, vol. 537, no. 2, pp. 1054–1062. DOI:https://doi.org/10.1086/309059.
5. Matthaeus W.H., Weygand J.M., Dasso S. Ensemble space-time correlation of plasma turbulence in the solar wind. Phys. Rev. Lett. 2016, vol. 116, no. 245101. DOI: 10.1103/ PhysRevLett.116.245101.
6. Oliveira D.M. Magnetohydrodynamic shocks in the interplanetary space: A theoretical review. Braz. J Phys. 2017, vol. 47, pp. 81–95. DOI:https://doi.org/10.1007/s13538-016-0472-x.
7. Park B., Pitňa A., Šafránková J., Němeček Z., Krupařová O., Krupař V., Zhao L., Silwal A. Change of spectral properties of magnetic field fluctuations across different types of interplanetary shocks. Astrophys. J. Lett. 2023, vol. 954, no. 2. DOI:https://doi.org/10.3847/2041-8213/acf4ff.
8. Pitňa A., Šafránková J., Němeček Z., Ďurovcová T., Kis A. Turbulence upstream and downstream of interplanetary shocks. Front. Phys. 2021, vol. 8, no. 626768. DOI:https://doi.org/10.3389/fphy.2020. 626768.
9. Rakhmanova L.S., Riazantseva M.O., Borodkova N.L., Sapunova O.V., Zastenker G.N. Impact of interplanetary shock on parameters of plasma turbulence in the Earth’s magnetosheath. Geomagnetism and Aeronomy. 2017, vol. 57, no. 6, pp. 664–671. DOI:https://doi.org/10.1134/S00 16793217060093.
10. Šafránková J., Němeček Z., Přech L., Zastenker G., Čermák I., Chesalin L., et al. Fast solar wind monitor (BMSW): Description and first results. Space Sci. Rev. 2013, vol. 175 (1-4), pp. 165–182. DOI:https://doi.org/10.1007/s11214-013-9979-4.
11. Šafránková J., Němeček Z., Němes F., Přech L., Pitňa A., Chen C.H.K., Zastenker G.N. Solar wind density spectra around the ion spectral break. Astrophys. J. 2015, vol. 803, p. 107. DOI:https://doi.org/10.1088/0004-637X/803/2/107.
12. Šafránková J., Němeček Z., Němes F., Přech L., Chen C.H.K., Zastenker G.N. Power spectral density of fluctuations of bulk and thermal speeds in the solar wind. Astrophys. J. 2016, vol. 825, p. 121. DOI: 10.3847/ 0004-637X/825/2/121.
13. Sapunova O.V., Borodkova N.L., Yermolaev Yu.I., Zastenker G.N. Spectra of fluctuations of solar wind plasma parameters near a shock wave. Cosmic Res. 2024, vol. 62, no.1, pp. 1–9. DOI:https://doi.org/10.1134/S0010952523700843.
14. Schekochihin A.A., Cowley S.C., Dorland W., Hammett G.W., Howes G.G., Quataert E., Tatsuno T. Astrophysical gyrokinetics: kinetic and fluid turbulent cascades in magnetized weakly collisional plasmas. Astrophys. J. Suppl. Ser. 2009, vol. 182, no. 1, pp. 310–377. DOI:https://doi.org/10.1088/0067-0049/182/1/310.
15. Smith C.W., Mullan D.J., Ness N.F., Ruth M.S., John S. Day the solar wind almost disappeared: Magnetic field fluctuations, wave refraction and dissipation. Geophys. Res. 2001, vol. 106, pp. 18625–18634. DOI:https://doi.org/10.1029/2001JA000022.
16. Zastenker G.N., Safrankova J., Nemecek Z., Prech L., Cermak I., Vaverka I., Komarek A., Voita J., et al. Fast measurements of parameters of the solar wind using the BMSW instrument. Cosmic Res. 2013, vol. 51, p. 78. DOI:https://doi.org/10.1134/S00 10952513020081.
17. Zhao L.-L., Zank G.P., He J.S., Telloni D., Hu Q., Li G., Nakanotani M., Adhikari L., et al. Turbulence and wave transmission at an ICME-driven shock observed by the solar orbiter and wind. Astron. and Astrophys. 2021, vol. 656, no. A3. DOI:https://doi.org/10.1051/0004-6361/202140450.
