[en] The development of an intense negative ion magnetron source, capable of extracting short pulsed negative ion beams of several hundred mA, was previously reported. For most particle accelerators these pulsed beams are more than adequate, but for efficient neutral injector systems in future fusion reactors, multi-ampere dc negative ion beams are required. In the past two years significant progress was made in the development of three direct extraction negative ion sources. The first source, the hollow discharge duoplasmatron (HDD), was extensively studied and optimized up to currents of 60 mA. With the second source, the magnetron, a beam current of almost one ampere has been obtained for more than ten milliseconds beam pulses. Several prototype Penning sources were constructed with yields similar as the magnetrons and with the expected advantage of higher gas efficiency. In order to improve knowledge of the origin of negative ion production, a program has started to measure the pertinent plasma parameters of the above mentioned sources by spectroscopic means and electrostatic probes. A first attempt was made to integrate a magnetron source in a 150 kV accelerator structure; so far, beams of 200 mA were accelerated up to 120 kV for several millisecond beam pulses