Ion-driven Instabilities in the Inner Heliosphere. I. Statistical Trends

@article{Martinovi2021IondrivenII,
  title={Ion-driven Instabilities in the Inner Heliosphere. I. Statistical Trends},
  author={Mihailo M. Martinovi{\'c} and Kristopher Gregory Klein and Tereza Ďurovcov{\'a} and Benjamin L. Alterman},
  journal={The Astrophysical Journal},
  year={2021},
  volume={923}
}
Instabilities described by linear theory characterize an important form of wave–particle interaction in the solar wind. We diagnose unstable behavior of solar wind plasma between 0.3 and 1 au via the Nyquist criterion, applying it to fits of ∼1.5M proton and α particle Velocity Distribution Functions (VDFs) observed by Helios I and II. The variation of the fraction of unstable intervals with radial distance from the Sun is linear, signaling a gradual decline in the activity of unstable modes… 

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