Electric current in a unipolar sunspot with an untwisted field

We apply the Return Flux (RF) sunspot model to a round, unipolar sunspot observed by H. Kawakami (1983). Solving the magnetohydrostatic problem using the gas pressure deficit between the umbral and quiet-Sun atmospheres as a source function, we find a distribution of electric current density in an untwisted, unipolar sunspot as a function of height and radial distance from the sunspot center. Maximum electric current density is about 32 m A m−2 at the bottom of the sunspot.