microMonteCarlo

A micro project for playing around with Monte Carlo simulations. This project was initially for simulating Electron Transport using Monte Carlo methods. For more information on Monte Carlo methods for electron transport see here: https://en.wikipedia.org/wiki/Monte_Carlo_methods_for_electron_transport

Installation

This project is built and validated in MATLAB R2022a running on Ubuntu 22.04.03 and MacOS 14 Sonoma. However it should work in any MATLAB version and in Windows.

In Ubuntu or MacOS open a terminal and clone the repo, then open the project in MATLAB. To clone the project enter this in a terminal:

git clone https://github.com/JonathanALevine/microMonteCarlo

Example usage

To set up a simulation with random scattering disabled set scattering = 0 in config.m. config.m contains other variables that control the conditions of the simulation. num_particles sets the number of particles and distribution_type sets the initial distribution of the particle velocities. The example MATLAB code below sets distribution_type = 'MB' for a Maxwell-Boltzmann distribution.

% Constants
global m0 m T k tau Pscat dt epochs;
global num_particles distribution_type scattering;
global vth;
global world;
global dt;


m0 = 9.10938356*10^(-31); %Electron rest mass
m = 0.26*m0;
T = 300; % temperature in kelvin
k = 1.38064852*10^(-23); %Boltzmann Constant
tau = 0.2*10^(-12);
world.length = 400*10^(-9);
world.height = 200*10^(-9);
vth = sqrt(2*k*T/m);
dt = world.height/vth/100;
epochs = 250;
Pscat = 1 - exp(-dt/tau);
% Simulation controls
num_particles = 250;
distribution_type = 'MB';
scattering = 0;

World boundary conditions are controlled by WorldBoundaryHandler.m. with specular_boundaries = 1 the borders of the world are rigid causing particles to bounce off the borders. With specular_boundaries = 0 the horizontal borders are rigid but the vertical borders wrap around, so the world is basically a cylinder like this:

main.m runs the simulation and an example is below:

close all;  
clear; %intialization
set(0,'DefaultFigureWindowStyle','docked')
config; % load the simulation configurations
states = GenerateStates(num_particles, distribution_type);
run(states, epochs);

Features

List down the features of your project here. For example:

• Electron movement under an electric field is implemented in Part5.m in legacy. Work is ongoing at tranferring this to main. PR's are welcome if you would like to implement this.
• This project currently does not have tests. This is needed. PR's are welcome if you would like to implement this.
• For code to record the simulations a videos in .avi see main.m and run.m in readme-file. See https://itsfoss.com/convert-video-gif-linux/ on how to convert .avi files to gif via Linux terminal commands.