Electron and magnetic turbulence fluctuations in the interstellar medium measured by scintillations of pulsar radio waves and in-situ Voyagers 1 & 2 observations

Professor Lou-Chuang Lee from Institute of Earth Sciences, Academia Sinica


In 1941, Kolmogorov proposed the first hydrodynamic turbulent model for the fluid and gave the well-known power law index, -11/3, of energy spectrum. In 1976, Lee and Jokipii first suggested that the interstellar turbulence at the length scale λ of 108m to 1018m (100 light-years) also has a Kolmogorov-like spectrum based on observations of radio wave scintillations and interstellar clouds. Armstrong et al. (1995) constructed the composite spectrum extending from 106m to 1018m based on ground telescope observational results. In 1977, two satellites named Voyager 1 & 2 were launched. Voyager 1 (2) entered the local interstellar medium in 2012 (2018). Kun-Han Lee and Lou Lee (2019) uses the data from in situ measurements to determine the spectrum of the turbulent density fluctuations from 50m to 2x1012m (15 au) in the local interstellar medium. By combining the in situ measured spectrum and the earlier remote observed data, they obtain a composite spectrum, the Grand Power Law in the Milky Way, extending from 50m to 1018m (100 light-years), over 16 orders of magnitude in length scale. In this talk, the interaction of solar wind with Earth’s magnetosphere and with interstellar medium will also be discussed.

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