Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun

Abstract

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disc center in the "Away" ("Toward") IMF sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the "Away" ("Toward") sector is $1.54\pm 0.21_{\mathrm{stat}}\pm 0.20_{\mathrm{syst}}$ ($1.62\pm 0.15_{\mathrm{stat}}\pm 0.22_{\mathrm{syst}}$) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

arXiv comment7 pages, 4 figures

References in corpus (5)

• Multi-Tev Gamma-Ray Observation from the Crab Nebula Using the Tibet-III Air Shower Array Finely Tuned by the Cosmic-Ray Moon's Shadow
• Probe of the Solar Magnetic Field Using the "Cosmic-Ray Shadow" of the Sun
• A study of the shadowing of galactic cosmic rays by the sun in a quiet phase of solar activity with the Tibet air shower array
• Mean Interplanetary Magnetic Field Measurement Using the ARGO-YBJ Experiment
• Coronal Magnetic Fields Derived from Simultaneous Microwave and EUV Observations and Comparison with the Potential Field Model

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• Influence of Earth-Directed Coronal Mass Ejections on the Sun's Shadow Observed by the Tibet-III Air Shower Array
• Role of magnetic arcades in explaining the puzzle of the gamma-ray emission from the solar disk
• Monitoring the daily variation of Sun-Earth magnetic fields using galactic cosmic rays
• Simulating gamma-ray production from cosmic rays interacting with the solar atmosphere in the presence of coronal magnetic fields