This paper presents a concept of coupling energy to fusion plasmas by spatially distributed and programmable compact energetic neutral beams. These energetic sources are pencil neutral beams with energy from 1 KeV up to 4 MeV. They are formed from the electron transfer between accelerated positive and negative ions in well-proven Radio Frequency Quadrupole (RFQ) structures. Symmetry in positive and negative ion plasmas favors the trapping of both species in adjacent potential wells of a travelling wave. Since this source does not require a large charge-exchange cell and high voltage sources, its compact size allows it to be positioned at multiple locations around the fusion device with various angles of injection.

The motivation for this paper is to usher a new paradigm in the heating, fueling and diagnosis of fusion devices. Large fusion device of meter scale size will need energetic beams to penetrate to its center for heating, fueling and diagnostics. Kinetic instabilities might require ion injection in specific regions of phase space at particular times. Since the beam density scales favorably with decreasing size, we have utilized advances in computer and micro-fabrication and nanotechnology to design a multiple module beam injection system. This approach makes it possible to program each beam module such that beam injection is triggered by special events inside a dynamic fusion plasma.

Current research devices will need inexpensive neutral beams to test their concepts at reasonably high ion energy. This proposed program is designed to demonstrate the versatility of such programmable compact beams in fusion research and ultimate reactor applications. The same principles used to produce these energetic neutral beams are equally applicable to produce neutralized beams that have potential applications in inertial fusion to prevent charge buildup at the target.1

We will first describe our method of producing neutral beam sources based on the wave-acceleration process and the wave enhanced charge-transfer process. We will then describe how our beam sources can be tested in ECRH produced linear magnetized plasma equipped with ICRH and mirror confinement.

The overall objective is to demonstrate the viability and versatility of these compact neutral beams for fusion. Physics issues connected with profile and instability control and the simulation of alpha particles are topics that can be investigated.