Related Experiment Video
Updated: Jul 30, 2026
11:20
Investigation of Early Plasma Evolution Induced by Ultrashort Laser Pulses
Published on: July 2, 2012
Sawtooth evolution during JET ion-cyclotron-resonance-heated pulses
1School of Mathematical Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom.
Physical Review Letters
|October 4, 2000
Summary
The Joint European Torus deuterium-tritium campaign observed that ion-cyclotron-resonance-heated (ICRH) pulses significantly impact sawtooth behavior. Minority ion populations correlate with stabilization of the ideal internal kink, influencing sawtooth duration.
Area of Science:
- Plasma physics
- Fusion energy research
Background:
- Sawtooth oscillations are common in tokamak plasmas.
- Ion-cyclotron-resonance-heating (ICRH) is a key technique for heating plasma in fusion devices.
- Understanding sawtooth dynamics is crucial for achieving stable fusion conditions.
Purpose of the Study:
- To investigate the relationship between ICRH minority ion populations and sawtooth characteristics.
- To determine the stabilizing effect of ICRH on ideal internal kinks during deuterium-tritium operations.
Main Methods:
- Analysis of data from the Joint European Torus (JET) deuterium-tritium campaign.
- Calculation of kinetic-fluid Magnetohydrodynamic (MHD) energy from energetic ion measurements.
- Comparison of calculated energy evolution with observed sawtooth duration.
Main Results:
- Substantial evolution of both sawtooth characteristics and ICRH minority ion populations was observed.
- A strong correlation was found between sawtooth duration and the stabilization of the ideal internal kink by minority ions.
Conclusions:
- Minority ion populations play a significant role in stabilizing ideal internal kinks.
- ICRH has a demonstrable effect on sawtooth stability in tokamak plasmas, crucial for fusion energy development.
Related Concept Videos
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:17NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
A pulse is a short burst of radio waves distributed over a range of frequencies that simultaneously excites all the nuclei in the sample. Upon passing a radio frequency pulse along the x-axis, the nuclei absorb energy corresponding to their Larmor frequencies and achieve resonance. This shifts the net magnetization vector from the z-axis toward the transverse plane. This angle of rotation of the magnetization vector, or the flip angle, is proportional to the duration and intensity of the pulse.
01:31Oscillations In An LC Circuit
An idealized LC circuit of zero resistance can oscillate without any source of emf by shifting the energy stored in the circuit between the electric and magnetic fields. In such an LC circuit, if the capacitor contains a charge q before the switch is closed, then all the energy of the circuit is initially stored in the electric field of the capacitor. This energy is given by
01:10Generating Electromagnetic Radiations
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. Starting in 1887, he performed a series of experiments that confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz used an alternating-current RLC (resistor-inductor-capacitor) circuit that resonated at a known frequency and connected it to a loop of wire. High voltages induced across the gap in the...
01:20Atomic Emission Spectroscopy: Overview
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
01:19Inductively Coupled Plasma Atomic Emission Spectroscopy: Principle
Inductively coupled plasma (ICP) is the most widely used plasma source in atomic emission spectroscopy (AES), also known as Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The ICP source, or torch, consists of three concentric quartz tubes with argon gas flowing through them. A spark from a Tesla coil initiates the ionization of argon, generating a high-temperature plasma.
The ions and electrons produced interact with the fluctuating magnetic field created by a water-cooled...
The ions and electrons produced interact with the fluctuating magnetic field created by a water-cooled...