Experimental details of operation and plasma flow are presented for bucket ion sources having magnetic flux that bridges the source between the regions of electron injection and ion extraction. The basic goal is to increase the atomic fraction of hydrogen and deuterium by 15% and yet retain an ion‐flux‐density uniformity over the extraction region to within ±7%. A rod structure containing permanent magnets produces a known bridging flux filter across a well‐defined region. This provides an experimental apparatus useful for the study of the effect of magnetic flux on the source plasma flow. The parameters of filter position, filter strength, filter orientation, arc power, and gas pressure are related to species fractions, profile uniformity, and electrical efficiency. The option of having the bridging flux without a rod structure is presented, and experimental results of sources thought to contain this field configuration are discussed.