Copasetic Flow

 As always, look to the bottom of the post for background on what's going on. Finally, enough of theory and presentations!  I got back to the lab today!  Here’s the apparatus I built/used. NOTE:   As always, look to the bottom of the post for background on what's going on. No, the oscilloscope is not sticking its tongue out, that’s a floppy disc.  Remember those?   The small solenoid is what’s deemed a pickup coil.  It’s the first prototype, of the coil that will be used to measure the actual currents and magnetic fields produced by the can crusher magnet.  It’s exactly what it looks like, six complete turns made from a jumper wire.  The Styrofoam cup is to avoid abusing the small magnet block too much when it’s dropped.   The ‘scope pictured can capture a single waveform.  Here, it’s slowed way down to make a sweep over the course of several seconds.  It’s being used to look at the signal from the coil as the magnet is dropped through it.  E

OK, so that was quite the title.  I haven't done one of these in a while, but classes are about to start again and i figured I may as well get started deriving things again.  Plus, I had to do it for the can crusher magnet simulation code [1] for the experiment [3].  Here's what's really going on.  I have a Sage function that will give me the magnetic field in the z direction produced by a coil of wire that sits at z = 0 and a has a radius of 'rcoil'.  I'd like to know the magnetic field produced by the loop of wire along a circular path that is perpendicular to the plane of the current carrying coil.  A circular path perpendicular to the plane of a coil kind of begs for spherical coordinates, but the routine I have takes a z coordinate and a radius coordinate in the cylindrical coordinate system.  In the picture above, the circular path is shown, and the coil of wire is at the diameter of the circle and perpendicular to the page.  Note:  For those reading on

I'm deeper into the planning for this summer's experimental search for H-Rays [1].  I've abandoned my previous superconducting magnet designs in favor of a much simpler pre-existing yoke magnet that's sitting out in the hallway. The pole pieces are in the center of the picture and are retractable using the knobs on the edges of the magnet.  The resulting gap between the pole pieces is where the Dewar will sit,see the picture below: The Dewar sitting between the pole pieces has created a new theoretical issue.  It's only theoretical for the moment though.  Once we have numbers to go with the theory, we'll find out if our Dewar will wind up looking like this[3][4]: As  +Peter Terren  can tell you, rapidly changing magnetic fields like we hope to generate for quenching our superconducting sample will cause Lenz's law eddy currents that create opposing magnetic fields and resulting forces applied to the surfaces that contain the conductors.  

I tried out a little quickie experiment in the lab this afternoon. In short: a coil with a changing current, (AC), placed on a non-ferromagnetic conductor, like aluminum, will induce an opposing magnetic field and levitate. You can read all about the effect caused by eddy currents , on Wikipedia, and watch what happened in the lab here:

This installment of “It’s Obvious. Not!” looks at: Book: “Classical Dynamics of Particles and Systems” Edition: third Authors: Jerry B. Marion and Stephen T. Thornton Publisher: Harcourt Brace Jovanovich Page: 68 This post looks at Example 2.10 that investigates the motion of a charged particle in a magnetic field. The example is fairly straightforward with one exception. When determining the equations of motion, the authors propose a solution for the system of differential equations discussed below and reference example C.2 of Appendix C. It’s not immediately apparent how to use Example C.2 to arrive at the authors’ solution, so the steps are outlined in detail here. If you have questions, or suggestions, all comments are always welcome! The original system of coupled differential equations is: First, the authors’ differentiate both equations and then substitute the results into the other: at this point, the book suggests using the technique of ex