A source for a high density electrically neutral beam of combined positive and negative particles suitable for bombardment and heating of a pellet of nuclear fusion material to fusion temperature. A source mounted in a housing with a spherical substrate and providing free elements at the surface thereof, an electron beam for ionizing the free elements to produce positive ions, first, second and third grids spaced from each other along beam paths, and electron emitters, all for providing positive ion beams and electron beams at the same velocity for mixing to provide an overall neutral electrical charge. A porous substrate for passing a gas under pressure to the surface for ionizing. A porous substrate charged with solids, and a heater for vaporizing the solids for passing to the surface for ionizing. A source housing including precision ceramic rings with metal flanges, with substrate and grid structures carried on the flanges, with the flanges joined as by heliarc welding at their peripheries to provide a rigid mechanical and vacuum tight structure, with metal spacer rings between ceramic rings when desired.

Discharge apparatus comprises a vacuum envelope which is evacuated by a pamping apparatus. In the envelope, an anode and a hollow cathode are disposed and are connected to an arc power supply. A disk having an orfice covers one end of the hollow cathode. A low pressure gas is supplied from a gas source to the envelope through the hollow cathode and the orifice, the gas pressure in the hollow cathode being maintained higher than that in the envelope. The hollow cathode and the disk are made of an electrically conductive material and are connected to an ignition power supply. Before effecting discharging between the anode and the hollow cathode, the ignition power supply causes an ignition between the disk and the inner surface of the hollow cathode.

Method and apparatus for employing a plasma produced in a radio-frequency discharge to enhance electrostatic precipitation. The plasma is generated in an auxiliary gaseous stream, and the plasma is introduced into a primary fluid stream flowing toward or in an electrostatic precipitation zone. The plasma causes ionization of the auxiliary gaseous stream, and the ionized gaseous stream charges the particles in the primary fluid stream. The primary fluid stream in which the particles are entrained flows in a primary duct toward an electrostatic precipitator containing the precipitation zone. A plasma generator generates plasma in the auxiliary gaseous stream to cause ionization thereof; and a secondary duct conducts the plasma into the primary stream for charging particles in the primary fluid stream. The charged particles then flow in the primary fluid stream into the precipitator.

A plasma reactor with rf power inductively coupled into the reactor chamber to produce an rf magnetic field substantially perpendicular to a pedestal on which a wafer is placed for processing. Said pedestal is a powered electrode to which power is coupled to control the sheath voltage of the pedestal. This reactor is particularly suitable for soft etches and processes in which it is advantageous to couple much more power into ion production than into free radical production.

A method of transporting substances in plasma streams to and depositing them on a target in which the vapors of two or more selected materials are turned into separate ionized plasmas in separate plasma generating chambers, the plasmas are effused from their respective chambers due to the difference in plasma density between the inside and outside of the chamber to form separate plasma streams and the plasma streams are joined to form a single stream which is conducted to the surface of a substrate by means of axial magnetic fields which also serve to converge the plasma streams. In another embodiment, a single stream is branched by a magnetic field to form plural streams which are conducted to different substrates or different points on the same substrate.