  The Sun's corona has interested researchers for multiple reasons, including
the search for solution for the famous coronal heating problem and a purely
practical consideration of predicting geomagnetic storms on Earth. There exist
numerous different theories regarding the solar corona; therefore, it is
important to be able to perform comparative analysis and validation of those
theories. One way that could help us move towards the answers to those problems
is the search for observational methods that could obtain information about the
physical properties of the solar corona and provide means for comparing
different solar corona models.
  In this work we present evidence that VLBI observations are, in certain
conditions, sensitive to the electron density of the solar corona and are able
to distinguish between different electron density models, which makes the
technique of VLBI valuable for solar corona investigations. Recent works on the
subject used a symmetric power-law model of the electron density in solar
plasma; in this work, an improvement is proposed based on a 3D numerical model.
