A new inner heliosphere proton parameter data set from the Helios mission

Abstract

In the near future, Parker Solar Probe and Solar Orbiter will provide the first comprehensive in-situ measurements of the solar wind in the inner heliosphere since the Helios mission in the 1970s. We describe a reprocessing of the original Helios ion distribution functions to provide reliable and reproducible data to characterise the proton core population of the solar wind in the inner heliosphere. A systematic fitting of bi-Maxwellian distribution functions was performed to the raw Helios ion distribution function data to extract the proton core number density, velocity, and temperatures parallel and perpendicular to the magnetic field. We present radial trends of these derived proton parameters, forming a benchmark from which new measurements in the inner heliosphere will be compared to. The new dataset has been made openly available for other researchers to use, along with the source code used to generate it.

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Cited by in corpus (16)

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• The origin of slow Alfvénic solar wind at solar minimum
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• Alpha particle thermodynamics in the inner heliosphere fast solar wind
• Statistical analysis of intermittency and its association with proton heating in the near Sun environment
• Linear Stability in the Inner Heliosphere: Helios Reëvaluated
• Radial evolution of stochastic heating in low-$\beta$ solar wind
• Ion-Driven Instabilities in the Inner Heliosphere I: Statistical Trends
• Preferential Proton over Electron heating from coherent structures during the first perihelion of Parker Solar Probe
• Heating of the Solar Wind by Ion Acoustic Waves
• Ion-Driven Instabilities in the Inner Heliosphere II: Classification and Multi-Dimensional Mapping
• On the evaluation of solar wind's heating rates
• Evolving Solar Wind Flow Properties of Magnetic Inversions Observed by Helios
• Radial evolution of thermal and suprathermal electron populations in the slow solar wind from 0.13 to 0.5 au : Parker Solar Probe Observations