Global Maps of the Solar Corona Magnetic Field Created for the First Time

Coronal Magnetic Field Lines PFSS

Coronal magnetic area traces obtained from the PFSS mannequin. Credit: Z.-H. Yang et al., Science (2020)

The Sun is a magnetized star. Its magnetic area is actually three dimensional and it occupies all layers of the photo voltaic environment. However, routine measurements of the photo voltaic magnetic area have solely been achieved on the photospheric degree, or the photo voltaic floor.

Lacking exact information in regards to the magnetic area within the outermost photo voltaic environment, the corona, has impeded our understanding of the photo voltaic magnetism and lots of phenomena within the photo voltaic environment.

An worldwide staff led by TIAN Hui, a professor from each Peking University and National Astronomical Observatories of Chinese Academy of Sciences (NAOC), has measured the worldwide magnetic area of the photo voltaic corona for the primary time. The examine was revealed in Science in August 2020.

The staff used observations from the Coronal Multi-channel Polarimeter (CoMP), an instrument operated by the High Altitude Observatory, National Center for Atmospheric Research, USA.

Coronal Magnetic Field Strength and Direction

A map of the coronal magnetic area power (left) and route (proper) superimposed on a coronal picture taken by the AIA instrument on the Solar Dynamics Observatory. Credit: YANG Zihao and TIAN Hui

More than 20 years in the past, a method referred to as coronal seismology or magneto-seismology has been launched for coronal magnetic area measurements. This methodology makes use of some kinds of oscillations or waves which are noticed in coronal constructions.

However, these oscillations/waves are simply sometimes noticed in small areas of the corona, and thus their potential for magnetic area measurements is proscribed.

CoMP is a coronagraph with a 20-cm aperture. It can observe the photo voltaic corona utilizing the Fe XIII 1074.7 nm and 1079.eight nm infrared spectral traces. The Doppler picture sequence obtained from CoMP observations usually reveal the prevalence of propagating periodic disturbances, indicating the ever-present presence of transverse plasma waves within the corona.

The staff utilized the magneto-seismology methodology to those pervasive waves. They prolonged the beforehand developed wave-tracking approach to the entire area of view, and obtained the distribution of the wave propagation velocity within the world corona.

They additionally obtained a worldwide map of the coronal density from observations of the 2 Fe XIII traces. Combing the maps of wave propagation velocity and density, they mapped the magnetic area within the world corona.

“By applying this technique to CoMP-like instruments in the future, global coronal magnetic field maps could be routinely obtained, filling in the missing part of the measurements of the Sun’s global magnetism,” mentioned Prof. TIAN.

Such measurements might present vital data to advance our understanding of the bodily mechanisms answerable for photo voltaic eruptions and the 11-year sunspot cycle.

For extra on this analysis, learn:

Reference: “Global maps of the magnetic field in the solar corona” by Zihao Yang, Christian Bethge, Hui Tian, Steven Tomczyk, Richard Morton, Giulio Del Zanna, Scott W. McIntosh, Bidya Binay Karak, Sarah Gibson, Tanmoy Samanta, Jiansen He, Yajie Chen and Linghua Wang, 7 August 2020, Science.
DOI: 10.1126/science.abb4462

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