Magnetic null points due to multiple sources of solar photospheric flux

How common are magnetic null points in the highly complex magnetic field of the solar atmosphere? In this work we seek to model the magnetic structure of quiet regions by placing magnetic sources and sinks on a hexagonal netw ork of supergranule cells to represent the intense magnetic fields that occ ur at the boundaries of these cells. The resulting potential coronal magnet ic field is then computed analytically and searched numerically for magneti c null points, which are classified according to their types and spine dire ctions. Two relations from the theory of vector fields relate the numbers o f null points to the numbers of sources and sinks and these are used to che ck the numerical results. Previous results relating these quantities for mo nopolar and dipolar magnetic fields are described and a new one for a parti cular class of quadrupolar fields arising in this study is derived. We mode l a three-cell configuration and study the effects of increasing the streng th of a central sink and of moving the central sink. A twelve-cell configur ation is studied in lesser detail.