Related Experiment Video
Updated: Aug 27, 2025

Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas
Published on: May 25, 2021
Electron Modulational Instability in the Strong Turbulent Regime for an Electron Beam Propagating in a Background
Haomin Sun1,2,3, Jian Chen4, Igor D Kaganovich1
1Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA.
Abstract:
We study collective processes for an electron beam propagating through a background plasma using simulations and analytical theory. A new regime where the instability of a Langmuir wave packet can grow locally much faster than ion frequency is clearly identified. The key feature of this new regime is an electron modulational instability that rapidly creates a local Langmuir wave packet, which in its turn produces local charge separation and strong ion density perturbations because of the action of the ponderomotive force, such that the beam-plasma wave interaction stops being resonant. Three evolution stages of the process and observed periodic burst features are discussed. Different physical regimes in the plasma and beam parameter space are demonstrated for the first time.
Related Concept Videos
The Uncertainty Principle
Electrostatic Boundary Conditions in Dielectrics
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
Atomic Nuclei: Nuclear Relaxation Processes
Transmission Electron Microscopy
Magnetic Moment of an Electron
Thomson's e/m Experiment
A particle with charge q, speed v, and mass m enters an area from the top, where the magnetic and electric fields are perpendicular both to the particle's motion and to one another. The...

