A BNL‐type toroidal H−source with circular permanent magnet cusps has been designed and tested. The volume of the plasma chamber is 452 cm3. The source plasma is created by a discharge initiated from a 1 mm diameter hot tungsten filament. The discharge was operated in a pulsed mode with a maximum pulse length of 300 &mgr;sec, and a maximum discharge voltage of 200 V. For these tests, the source body was biased in the range of 1–10 kV. A permanent magnet mass filter was used to separate the extracted H−ions from the electrons. We have observed a maximum current density of 16 mA/cm2with an e/H−ratio of 16 when the operation conditions were as follows; an arc voltage of 190 V, 60 A filament current, and 10 kV extraction. The source pressure at the maximum output was estimated to be 8.2 mTorr.