Cross-section of nuclear fusions

In the context of nuclear fusion, the cross-section refers to the measure of the likelihood that two atomic nuclei will undergo a fusion reaction when they collide. It is typically denoted by the symbol “σ” (sigma) and has units of area. The cross-section for nuclear fusion depends on various factors, including the types of nuclei … Read more

Replace tool: Convert the express in Wolfram Mathematica to Javascript

from Wolfram Mathematica to JavaScript might require understanding the specific functionality of both languages, as they have different syntax and capabilities. Certainly! The FortranForm function in Mathematica is used to convert expressions into a form that is more suitable for use in Fortran code. It ensures that the syntax and formatting match the Fortran programming … Read more

Coulomb potential barrier

The Coulomb potential barrier, also known as the Coulomb barrier, is a concept in physics that refers to the energy barrier that must be overcome for two charged particles to interact or come close enough to undergo a specific process, such as nuclear reactions or particle interactions. It arises due to the electrostatic repulsion or … Read more

Matrix form of Vector operation

Matrix is a tool to deal with the linear algebra. Vector is usually used to describe most of the physical quantities those have both the direction and amplitude. The vector operations are usually very complicated in the vector algebra. A vector is a simple matrix. I try to obtain the matrix form of vector operation … Read more

A simple and fast tool to estimate the electron cyclotron wave propagation in tokamak plasma.

Electron cyclotron resonance heating is the simplest of the radio frequency heating methods. There is no evanescent region between the antenna and the plasma. However there may be cut-offs in the plasma. It turns out to provide remarkable advantages for heating of fusion plasma. An electromagnetic wave in the electron cyclotron resonance frequency range always … Read more

Transverse electric(TE) wave in circular waveguides

Circular waveguides offer implementation advantages over rectangular wave guide is that installation is much simpler when forming runs of turns and offsets. The uniform section in the gyrotron cavity is a circular waveguide. The working mode is usually a transverse electric mode in the cavity. Here is a calculator for the Transverse Electric mode in … Read more

Eigenmodes of the gyrotron cavity

Gyrotron is a microwave oscillators. It changes the DC energy to high power millimetre microwave. It has been successfully used in the magnetic confinement thermonuclear fusion research as the microwave source for the electron cyclotron resonance heating and current drive. A typical gyrotron cavity consists of a central section and one taper section at both … Read more

Weak form of Helmholtz equation

Weak form is an important tool for the analysis of electromagnetic problems. It is a bridge from the partial differential equations to the linear algebra. For example, the Helmholtz equation with wave number \(k_c\) is \(\nabla_t^2 \phi+k_c^2 \phi=0\) It is so-called “strong form”, in which the unknow is in the 2nd order differential operator. It … Read more

A way to memorize the boundary conditions

It is very important to specify boundary conditions at material interfaces and physical boundaries in order to get a full description of an electromagnetic problem. However the boundary conditions between two media is difficult to memorize. Here we present a way to memorize them. The maxwell’s equations are \(\nabla \times H=J+\partial_t D\) \(\nabla \times E=-\partial_t … Read more

Recognize the trigonometric functions again

We always learn the trigonometric functions from the geometry and use them to solve geometry problem. It it quite difficult to memorize some trigonometric identities. We re-define the sine and cosine function from the view of the solution of the ordinary differential equations in this article. It is similar with the Bessel functions. The Helmholtz … Read more