A New Approach to Calculate Coronal Electron Density: Simplified Van De Hulst’s Method

Abstract

Determining the electron density is a challenging task in solar corona studies, as it requires certain assumptions to be made, such as symmetric, homogeneous and radial distribution, thermal equilibrium, etc. In such studies, the observed 𝐾 corona brightness is based on the coronal electron density. An important paper on the calculation of electron density was published in 1950 by van de Hulst in an article titled “The Electron Density of the Solar Corona”. The author developed a method with some assumptions to calculate the electron density from the observed 𝐾 corona brightness. We presented here, a new simplified calculation method for the coronal electron density is presented. The integral equation solution given by van de Hulst is interpreted from a different perspective and the 𝐾 coronal electron density is calculated using only observational data without making any additional adjustments such as successive approximations and multiple attempts.

Keywords

• Sun
• Corona
• scattering
• polarization
• Astrometry and celestial mechanics
• eclipses

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