Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

1.1K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
1.1K
Atomic Nuclei: Nuclear Magnetic Moment00:59

Atomic Nuclei: Nuclear Magnetic Moment

2.9K
All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...
2.9K
Motion Of A Charged Particle In A Magnetic Field01:22

Motion Of A Charged Particle In A Magnetic Field

6.4K
A charged particle experiences a force when moving through a magnetic field. Consider the field to be uniform and the charged particle to move perpendicular to it. If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of motion, a charged particle follows a curved path. The particle continues to follow this curved path until it forms a complete circle. Another way to look at this is that the...
6.4K
Atomic Nuclei: Magnetic Resonance01:05

Atomic Nuclei: Magnetic Resonance

1.0K
The number of nuclear spins aligned in the lower energy state is slightly greater than those in the higher energy state. In the presence of an external magnetic field, as the spins precess at the Larmor frequency, the excess population results in a net magnetization oriented along the z axis. When a pulse or a short burst of radio waves at the Larmor frequency is applied along the x axis, the coupling of frequencies causes resonance and flips the nuclear spins of the excess population from the...
1.0K
Atomic Nuclei: Nuclear Spin State Population Distribution01:14

Atomic Nuclei: Nuclear Spin State Population Distribution

2.2K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
2.2K
Potential Due to a Magnetized Object01:24

Potential Due to a Magnetized Object

719
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
719

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Evaluation of the Effects of 50 Hz Magnetic Field Exposure on the Human Hematopoietic System in Humanized Mice.

Bioelectromagnetics·2026
Same author

The role of postoperative ultrasonography in the early detection of renal artery pseudoaneurysms after robot-assisted partial nephrectomy.

The journal of medical investigation : JMI·2026
Same author

Inhibition of ESCRT-III activates alternative pathways for protein degradation and secretion.

Neurochemistry international·2026
Same author

Insights into <i>In Vivo</i> Performance of Amorphous Solid Dispersions: Evaluation Using a Surrogate Marker for Drug Release Profiles and Pharmacokinetic Analysis.

Molecular pharmaceutics·2025
Same author

Report of the 5th International Symposium on Frontiers in Molecular Science (ISFMS 2025).

International journal of molecular sciences·2025
Same author

GWAS Identifies SNPs Associated With Severe Adverse Events and Efficacy in Advanced Renal Cell Carcinoma Treated With Nivolumab.

Cancer science·2025

Related Experiment Video

Updated: Dec 20, 2025

Magnetically Induced Rotating Rayleigh-Taylor Instability
06:42

Magnetically Induced Rotating Rayleigh-Taylor Instability

Published on: March 3, 2017

9.9K

Rotating Spokes, Ionization Instability, and Electron Vortices in Partially Magnetized E×B Plasmas.

Jean-Pierre Boeuf1, Masayuki Takahashi2

  • 1Laplace, Université de Toulouse, CNRS, INPT, UPS, 118 Route de Narbonne, 31062 Toulouse, France.

Physical Review Letters
|May 23, 2020
PubMed
Summary

Rotating spokes in E×B plasma devices are caused by electron heating and ionization at a double layer. This kinetic model explains spoke motion in both forward and retrograde directions, matching experimental observations.

More Related Videos

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
11:47

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Published on: December 22, 2018

9.5K
Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
07:17

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

Published on: August 1, 2017

13.0K

Related Experiment Videos

Last Updated: Dec 20, 2025

Magnetically Induced Rotating Rayleigh-Taylor Instability
06:42

Magnetically Induced Rotating Rayleigh-Taylor Instability

Published on: March 3, 2017

9.9K
A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
11:47

A 100 KW Class Applied-field Magnetoplasmadynamic Thruster

Published on: December 22, 2018

9.5K
Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
07:17

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry

Published on: August 1, 2017

13.0K

Area of Science:

  • Plasma physics
  • Space plasma physics
  • Astrophysics

Background:

  • E×B plasma devices exhibit rotating light emission regions, known as spokes.
  • These phenomena are observed in various plasma environments, including astrophysical contexts.

Purpose of the Study:

  • To investigate the kinetic mechanisms behind the formation and motion of rotating spokes in E×B plasma devices.
  • To explain the bidirectional (E×B and retrograde) motion of spokes.

Main Methods:

  • Development of a kinetic model to simulate plasma behavior.
  • Analysis of electron heating mechanisms, including ∇B drift and velocity shear-induced vortices.
  • Localization of enhanced ionization along a double layer.

Main Results:

  • Identified electron heating and enhanced ionization at the double layer interface as the primary drivers of spoke formation.
  • Demonstrated that ∇B drift and electron vortices contribute significantly to electron heating.
  • Successfully reproduced and explained both E×B and retrograde spoke motion.

Conclusions:

  • The kinetic model provides a comprehensive explanation for rotating spokes in E×B devices.
  • The findings elucidate the complex interplay of electric and magnetic fields in plasma dynamics.
  • This research offers insights into phenomena observed in both laboratory plasmas and astrophysical systems.