Related Experiment Video
Updated: Jan 27, 2026
08:42
Measurement of the Directional Information Flow in fNIRS-Hyperscanning Data using the Partial Wavelet Transform Coherence Method
Published on: September 3, 2021
3.5K
Direct Measurement of a Toroidally Directed Zonal Flow in a Toroidal Plasma.
T Nishizawa1, A F Almagri1, J K Anderson1
1Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Physical Review Letters
|April 2, 2019
Summary
Researchers observed a toroidally directed zonal flow in magnetic plasma confinement for the first time. This finding in reversed field pinch plasmas offers new insights into plasma turbulence and the quest for fusion energy.
Area of Science:
- Plasma Physics
- Fusion Energy Research
- Magnetohydrodynamics
Background:
- Zonal flows are crucial for regulating turbulence and transport in magnetically confined plasmas.
- In toroidal plasmas with strong toroidal magnetic fields, zonal flows are typically poloidally directed.
Purpose of the Study:
- To report the first observation of a toroidally directed zonal flow.
- To investigate the self-regulation mechanisms in plasma turbulence.
Main Methods:
- Measurements were conducted within the last closed flux surface of reversed field pinch plasmas.
- Plasma potential fluctuations and zonal flow strength were analyzed.
Main Results:
- A toroidally directed zonal flow was observed, a novel finding in this plasma configuration.
- A limit cycle oscillation between zonal flow strength and plasma potential fluctuations was identified.
Conclusions:
- The observed oscillation provides evidence for self-regulation in drift-wave-type plasma turbulence.
- These findings enhance the understanding of toroidal plasma behavior and aid gyrokinetic modeling for fusion energy development.
Related Concept Videos
01:27Toroids
3.9K
A toroid is a closely wound donut-shaped coil constructed using a single conducting wire. In general, it is assumed that a toriod consists of multiple circular loops perpendicular to its axis.
When connected to a supply, the magnetic field generated in the toroid has field lines circular and concentric to its axis. Conventionally, the direction of this magnetic field is expressed using the right-hand rule. If the fingers of the right hand curl in the current direction, the thumb points in...
When connected to a supply, the magnetic field generated in the toroid has field lines circular and concentric to its axis. Conventionally, the direction of this magnetic field is expressed using the right-hand rule. If the fingers of the right hand curl in the current direction, the thumb points in...
3.9K
01:09Directing Effect of Substituents: meta-Directing Groups
5.9K
Substituents on the benzene ring that direct an incoming electrophile to undergo substitution at the meta position are called meta directors. All meta directors either have a positive charge on the atom directly bonded to the ring or a partial positive charge. These groups function by withdrawing electrons from the ring through inductive and resonance effects. Consider the carbocation intermediates formed upon the addition of an electrophile on nitrobenzene at the...
5.9K
01:23Microbial Growth Measurement: Direct Methods
1.6K
Direct methods for measuring microbial populations in a culture are essential tools in microbiology, providing quantitative data for various applications. Among these, microscopic counts, plate counts, and serial dilution are widely used techniques, each with unique principles and applications.Microscopic CountsMicroscopic counting involves the use of a Petroff-Hausser chamber, a specialized microscope slide with a grid and defined depth. By observing a liquid culture under a microscope,...
1.6K
01:14Directing Effect of Substituents: ortho–para-Directing Groups
8.4K
Ortho–para directors are substituent groups attached to the benzene ring and direct the addition of an electrophile to the positions ortho or para to the substituent. All electron-donating groups are considered ortho–para directors. They donate electrons to the ring and make the ring more electron-rich. The ring is therefore susceptible to the addition of electrophiles. Substituents such as amino, hydroxy, or alkoxy, containing lone pairs on the atom adjacent to the ring, donate...
8.4K
01:25Directional Relays
601
Directional relays, essential for managing unidirectional fault currents, enhance the safety and efficiency of power systems. On power lines equipped with directional relays, faults downstream (to the right) of the current transformer typically cause the fault current to lag the bus voltage by approximately 90 degrees, known as the forward direction. In contrast, upstream (left-side) faults may result in the fault current leading the bus voltage by nearly 90 degrees, termed the reverse...
601
01:14Directional Terms
16.2K
Directional terms are essential for describing the relative locations of different body structures. For instance, an anatomist might describe one band of tissue as "inferior to" another, or a physician might describe a tumor as "superficial to" a deeper body structure. These terms often use comparative terms in pairs to trace out the relative locations of one body part to another or descriptions of body tissues like the deeper ones from superficially present with reference to...
16.2K