I recall seeing gas chromatography machines at Perkin Elmers and how they worked with RF coils with a vacuum and sample injected streaming thru the coil in a plasma flame.
Permanent magnets can be used in conjunction with radiofrequency (RF) plasma sources to generate and sustain plasma for various applications, such as plasma etching, thin film deposition, and surface treatment. Of course, CRT's had them for deflection alignment and corner correction.
In an RF plasma system, an electromagnetic field ionizes a gas, creating plasma. The plasma consists of charged particles, such as ions and electrons, and neutral particles, such as atoms and molecules. The charged particles can be accelerated by the electromagnetic field and can be used to modify the surface properties of materials or to deposit thin films.
Permanent magnets can be used in RF plasma sources to improve plasma properties and stability. The magnets are typically arranged in a specific pattern around the plasma chamber, creating a magnetic field that interacts with the charged particles in the plasma.
One important effect of the magnetic field is to confine the plasma near the chamber's center, away from the walls. This reduces the amount of gas that interacts with the walls, which can cause contamination or other unwanted effects.
The magnetic field also enhances the ionization process by increasing the probability of collisions between the gas molecules and the charged particles.
The use of permanent magnets in RF plasma sources can also improve the efficiency of the plasma generation process, by reducing the amount of RF power required to sustain the plasma. This is because the magnetic field can trap the charged particles in specific regions of the plasma, where they can interact with each other and with the gas more effectively, leading to a higher ionization rate and a more stable plasma.
Overall, using permanent magnets in RF plasma sources can improve plasma properties, stability, and efficiency, making them an important component in many plasma processing applications.