# Making Our Fusion Reactor Better

Update, November 9, 2018: the video above highlights some of the upgrade projects. This video was shot at about the halfway point of the 11-month schedule for all engineering upgrades. Β  Our lab, the DIII-D National Fusion Facility, has ended its experimental campaign and entered into a nearly one year period of upgrade construction. This…

# Colonel Mustard, in the Kitchen, with the Poison Gas

This is a Blast from the Past posting salvaged from the embers of my old website. Over the holiday weekend we had a family dilemma. Everyone wanted to play Clue, but no one wanted to go out in the holiday traffic to purchase the game. Fortunately, we found two people willing to walk to a…

# Capacitance of Concentric Cylinders

In this topic we will calculate the capacitance of a system of concentric cylindrical shells. The next figure presents the geometry of this topic. Two conducting and concentric cylindrical shells, infinitely long, constitute a system that some capacitance, C. Begin by noting that we can only determine the capacitance per unit length, C/L, because the…

# Kinetic and Radiative Energy of a Falling Electron

A charged particle that is accelerating emits radiation. Through the study of electrodynamics we often encounter moving charged particles without considering the issues of radiation. For example, the energy of a collection of charges may be calculated in part by solving for the energy involved in bringing those charges together from infinity. Radiation that they…

# Why Not to Use Aluminum in Your Langmuir Probes

I have made a fair number of Langmuir probes during the time I have been running experiments for my thesis. Some of the plasma facing material is aluminum, which I used because it was easy enough to machine that I could do it myself. The benefit of being able to do this myself is that…

# Electrostatic Potential with Spherical Boundary Conditions

One of the many mathematical techniques that are useful in the study of electrostatics is called the separation of variables method. This topic covers the application of this method to a situation in which the electrostatic potential in a spherically symmetric system is known. In such a system, the potential (potential and electrostatic potential are…

# Magnetic Field from a Cylinder’s Magnetization

It is not intuitively obvious how an object’s magnetization relates to the magnetic field it generates. To develop a better physical picture of this phenomena consider an object with a given magnetization and then solve for the resulting magnetic field, B. A cylinder of radius, R, and length, L, in which R << L (i.e.…

# Frequency Filtering in IDL Using the Butterworth Function

When IDL released version 6.3 they included a function called BUTTERWORTH. This function generates the Butterworth filter function commonly used in frequency filtering of time series data. I have previously used a Butterworth filter by generating my own array. Since it is almost always simpler to use provided functions, I decided to use this new…

# Circos Example: Fusion Research Collaborator Graphic

While serving as the newsletter editor for the U.S. Burning Plasma Organization, I implemented an Image of the Month feature intended to highlight exciting projects within the research community. Some of these described specific projects, such as the education and outreach work, while others were just curious graphics thatΒ don’t really highlight anything. An example from…

# Diary of a Graduate Thesis Experiment

The lengthy diary that follows was originally written in 2007. Diary of a Graduate Thesis Experiment The laboratory in which I am performing my thesis work (LAPD at UCLA) is used by researchers from all over the world. Groups that are using the device for a research project receive an allotted time in which to…