Related Experiment Video
Updated: Jan 2, 2026
09:55
Author Spotlight: Using Hyperpolarized Xenon-129 MRI to Study Lung Diseases
Published on: January 5, 2024
1.7K
Self-Generated Magnetic and Electric Fields at a Mach-6 Shock Front in a Low Density Helium Gas by Dual-Angle Proton
R Hua1, J Kim1, M Sherlock2
1Center for Energy Research, University of California, San Diego, La Jolla, California 92093, USA.
Physical Review Letters
|December 7, 2019
Summary
Researchers observed a self-generated magnetic field at a laboratory shock front using proton radiography. This magnetic field, crucial for understanding shock dynamics, was quantified and linked to the Biermann battery effect.
Area of Science:
- Plasma physics
- Astrophysical shocks
- Laboratory astrophysics
Background:
- Shocks are common in astrophysical and laboratory settings.
- Electric fields at shock fronts are well-studied, but self-generated magnetic fields are not.
- Magnetic fields can significantly influence shock profiles, especially in non-ideal geometries.
Purpose of the Study:
- To report the observation and characterization of a self-generated magnetic field at a laboratory shock front.
- To quantitatively measure the magnetic field strength.
- To investigate the plasma conditions and mechanisms responsible for magnetic field generation.
Main Methods:
- Mach ~6 shock propagation in a low-density helium gas system.
- Proton radiography from multiple angles to confirm magnetic field existence and measure strength.
- X-ray spectrometry to infer plasma density and temperature at the shock front.
- Particle-in-cell (PIC) simulations using the lsp code.
Main Results:
- Observation of a magnetic field at the shock front.
- Quantitative measurement of magnetic field strength between 5 and 7 Tesla.
- Constrained plasma conditions (density and temperature) at the shock front.
- Simulations attributed magnetic field generation to the Biermann battery effect (∇n_e × ∇T_e).
Conclusions:
- The Biermann battery effect is responsible for self-generating magnetic fields at laboratory shock fronts.
- The observed magnetic field is significant and influences shock dynamics.
- This study provides crucial insights into the interplay of electric and magnetic fields in shock phenomena.
Related Concept Videos
01:29Plane Electromagnetic Waves II
4.0K
Consider a plane wavefront traveling in position x-direction with a constant speed. This wavefront can be utilized to obtain the relationship between electric and magnetic fields with the help of Faraday's law.
4.0K
01:23Magnetic Field due to Moving Charges
11.3K
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
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...
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...
11.3K
01:27Induced Electric Fields: Applications
2.4K
An important distinction exists between the electric field induced by a changing magnetic field and the electrostatic field produced by a fixed charge distribution. Specifically, the induced electric field is nonconservative because it does not work in moving a charge over a closed path. In contrast, the electrostatic field is conservative and does no net work over a closed path. Hence, electric potential can be associated with the electrostatic field but not the induced field. The following...
2.4K
01:30Plane Electromagnetic Waves I
4.8K
The existence of combined electric and magnetic fields that propagate through space as electromagnetic (EM) waves is the most significant prediction of Maxwell's equations. As Maxwell's equations hold in free space, the predicted electromagnetic waves do not require a medium for their propagation. An EM wave comprises an electric field, defined as the force per charge on a stationary charge, and a magnetic field, which is the force per charge on a moving charge.
The EM field is assumed to be a...
The EM field is assumed to be a...
4.8K
01:22Motion Of A Charged Particle In A Magnetic Field
6.5K
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...
6.5K
01:19Magnetic Field Lines
5.4K
The representation of magnetic fields by magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. Each of the magnetic field lines forms a closed loop. The field lines emerge from the north pole (N), loop around to the south pole (S), and continue through the bar magnet back to the north pole.
Magnetic field lines follow several hard-and-fast rules:
Magnetic field lines follow several hard-and-fast rules:
5.4K