Related Experiment Video
Updated: Jun 15, 2026

Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas
Published on: May 25, 2021
Influence of the electron cross-field diffusion in negative ion sources with the transverse magnetic field and the
S Kuppel1, D Matsushita, A Hatayama
1Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Abstract:
The physical mechanisms involved in the extraction of H(-) ions from the negative ion source are studied with a PIC 2D3V code. The effect of a weak magnetic field transverse to the extraction direction is taken into account, along with a variable bias voltage applied on the plasma electrode (PE). In addition to previous modeling works, the electron diffusion across the magnetic field is taken into account as a simple one-dimensional random-walk process. The results show that without PE bias, the value of the diffusion coefficient has a significant influence upon the value of the extracted H(-) current. However, the value of this coefficient does not affect qualitatively the mechanism leading to the peak of extracted H(-) ion current observed for an optimum value of the PE bias.
Related Concept Videos
Electric Field
In the new picture, imagine that the first charge sets up an electric field independent of all other charges in the universe. When another charge comes in its vicinity, the second charge experiences an electric force depending on the electric field at that point. The source charge does not...
Electric Field of Two Equal and Opposite Charges
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
Induced Electric Fields: Applications
Magnetic Field due to Moving Charges
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Biasing of Metal-Semiconductor Junctions
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
The Electrical Double Layer
