Helios 1 E6: Hourly Particle Fluxes in Interplanetary Space from 0.3 to 1.0 AU

Helios-A and Helios-B spacecraft measured hourly averaged fluxes of electrons, protons, and alpha particles in interplanetary space from 0.3 to 1.0 Astronomical Units. The data, developed by the Federal Republic of Germany in cooperation with NASA, covers energy ranges from 0.3 to 2.0 MeV for electrons, 4.0 to 51 MeV for protons, and 2.0 to 48 MeV for alpha particles, with some channels providing standard deviations. Files are in ASCII format, each containing 10 hourly averages preceded by a header with start and stop times.

Use Cases

• Modeling solar energetic particle events based on proton and alpha particle flux measurements.
• Studying the modulation of galactic cosmic rays based on multi-channel particle data from 0.3 to 1.0 AU.
• Analyzing time-series correlations between electron fluxes and solar activity.
• Calibrating modern particle detectors against historical instrument measurements from the Helios mission.

Strengths

• Data covers a specific radial distance range from 0.3 to 1.0 Astronomical Units.
• Particle fluxes are measured in multiple energy channels for electrons (5), protons (6), and alpha particles (6).
• Instrument was calibrated prior to launch using radioactive sources, particle accelerators, and ground-level muons.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Column-level documentation is absent; field semantics must be inferred after download.
• The energy boundaries for two electron channels (0.2 to 0.8 and 0.8 to 2 MeV) are described as only rough estimates.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Measured by a particle telescope with five semiconductor detectors, a sapphire Cherenkov counter, and a scintillation counter on the Helios-A and Helios-B spacecraft.

Time Range

Hourly averages; specific mission dates are not provided in the input.

Freshness

Last updated 2026-03 13 07:05:32.388889; freshness should be verified.

Geography

Interplanetary space from 0.3 to 1.0 Astronomical Units from the Sun.