Copasetic Flow

+Jonah Miller  wrote about back of the envelope calculations today and it inspired me to finally write about the oft-quoted by fringe scientists work of Bryce DeWitt and the surprisingly less quoted work of Robert L. Forward. The link between Forward's work and Jonah's article is that Forward wrote an excellent pair of articles entitled "General Relativity for the Experimentalist" for the Proceedings of the IRE[1], (the precursor to the IEEE), and "Guidelines to Antigravity" for the American Journal of Physics[2].  In these two articles, Forward encouraged scientists and engineers to do back of the napkin general relativity by using a method of linearizing Einstein's field equations in in the weak field flat space limit so that they could be treated in the same manner as Maxwell's EM equations. So, where does Bryce DeWitt fit into the equation?  In 1966 he wrote an article about using superconductors to to detect gravitomagnetic fields...

The data taken last week showed a linear dependence between the voltage measured in the pick-up coil when the superconductor is levitated and the frequency of the current driving the levitating electromagnet. While reading an article on a susceptometer for superconductors , I came across the graph shown below that shows the decrease in the magnetic field of a solenoid driven at 5 V rms as frequency is increase.  A solenoid is an inductor with an impedance that is linearly dependent on the frequency of the current flowing through it.  The drop in the magnetic field is a result of of the impedance of the solenoid increasing with increasing frequency and reducing the current trough the coil. I'd like to see if the linear increase in the voltage required to attain levitation is just a result of the increasing impedance of the electromagnet.  My first task was to determine a relationshiop between the pick-up coil voltage and the voltage driving the electrom...

I was greeted by a hissing liquid nitrogen Dewar when I got to the lab today.  Apparently it's normal Dewar venting, but our last two didn't do this, so it was a bit interesting.  I was able to take more data today and there's a linear trend evolving.  As the frequency of the current driving the electromagnet is increased,the amplitude of the current has to be increased to achieve levitation of the superocnductor.  A picture of theresulting graph is shown below.  The x axis is frequency.  The y axis is the peak voltage detected on the pick-up coil wrapped around the electromagnet. Here's a picture of the modified pick-up coil. It's just three windings around the top of the magnet.

I'll be doing some reading this weekend trying to get some more information behind the experimental results I've seen this week.  The rough observations this week were: 1.  Levitation force seems to go down for the same peak magnetic field as frequency increases. 2.  The levitation force can be increased at a given frequency by increasing the peak magnetic field. I haven't found much research that measures the levitation force between an AC electromagnet and a superconductor.  I have found some interesting papers on the attenuation of magnetic flux trapped within a superconductor when an AC magnetic field is applied to the superconductor.  Two of the more interesting papers I've found are Ueda, H., Itoh, M., & Ishiyama, a. (2003). Trapped field characteristic of HTS bulk in AC external magnetic field. IEEE Transactions on Appiled Superconductivity, 13(2), 2283-2286. doi:10.1109/TASC.2003.813075 and Ogawa, J., Iwamoto, M., Yamagishi, K., Tsukamot...

Great news!  The bridged output mode on the Peavey amplifier I'm using here works!  That means I can apply roughly twice as much power to the levitation force providing electromagnet.  The bridge mode appeared not to be working two days ago.  A little reading of the manual provided the reason.  When in bridge mode, the speaker outputs don't like to be applied to any kind of ground.  I was trying to measure the output of the amplifier using a grounded oscilloscope.  Apparently this is what was causing the amplifier to shut itself off in bridged mode.  After removing the oscilloscope from the speaker outputs today, everything is working great.  Instead of hooking the scope directly to the electromagnet inputs, I attached it to  the pick-up coil.  As I mentioned a few days ago, this a better measure of the power available for levitation anyway. I don't have time to write up everything in a classy fashion at this point, but I would ...

Alternating current power can be reflected by a reactive load, (like an electromagnet). Ham radio operators are familiar with this concept and measure the amount of reflected power as the standing wave ratio, (SWR). As the frequency driving a ham radio antenna is changed away from the antenna's resonant frequency, the SWR increases, less power is driven into the antenna and more power is reflected back into the radio's amplifier. On Friday, I observed that the levitation height of the superconductor decreased when the frequency of the current driving the levitating electromagnet was increased. This is the expected result based on the experience of the other teams that tried to replicate Podkletnov's experiment. However, the same behavior would have resulted if power from the amplifier was being reflected without entering the electromagnet.  The amount of reflected power is usually measured with a directional wattmeter, or with an SWR meter.  I don't have either of...

The first oscillating magnetic field superconductor levitation tests yesterday went great. With the Peavey power amplifier driving the electromagnet, the superconductor levitated at frequencies up to 164 Hz. An interesting measurement problem arose that required the use of a math trick to compensate for the limitations of the oscilloscope. Our oscilloscope has a maximum vertical range of 5 volts per division. There are 8 vertical divisions on the screen, so as long as the oscillating voltage from the amplifier is less than or equal to 40 volts peak to peak, we can read its peak value by counting divisions on the oscilloscope screen. To attain the necessary levitation force however, the oscillating voltage applied to the electromagnet had to be greater than 40 V peak. Instead of readable trace like the one shown above, the oscilliscope looked like: There aren't enough divisions on the scope screen to read the voltage. This is where the math trick comes in. We know t...

While doing research for the NMSU Superconductor Gravity Experiment, I came across an article published by J.E. Hirsch of UCSD . He writes that his 'hole theory of superconductivity', (more on this in a later post), predicts that x-ray photons should be emitted by a superconductor similar in size to our sample when it changes from the superconducting to the non-superconducting state. The superconducting sample I'm using cycles between states each time a set of levitation force data is taken, so I decided to go ahead and try to detect the radiation predicted by Dr. Hirsch as a side project. A Geiger counter is being used as the radiation detector because it was readily available. Data acquisition with the Geiger detector turned out to be a little more work than I expected. My first thought was that I could simply record the beeps coming from the Geiger counter and then use Audacity to analyze the resulting audio file. There were a few issues that cropped up with thi...

One of the Podkletnov rotation magnetic field arrangements essentially 'points' a set of solenoid at the side of the superconducting disc. I came across a demonstration from the 1963 movie by Alfred Leitner about liquid helium that uses a very similar setup. The superconducting disc in this case has been replaced by a diamagnetic copper cylinder.

In his 1992 Physica C paper, Podkletnov references the use of a toroidal solenoid as the levitation coil for the superconducting disc. In Hathaway's 2003 reported replication attempt, he describes the same coils as pancake coils. It was unclear to me if a toroidal solenoid and a pancake coil were in fact the same device. It turns out that they are in fact different names for the same thing. See the page excerpted from the "Standard Tables and Equations in Radio-Telegraphy" by Bertram Hoyle, (1919), below. References: Podkletnov, Nieminen, Physica C, 203, (1992), 441 Hathaway, Cleveland, Bao, Physica C, 385, (2003), 488

Here's a suggestion for how the threaded two rotation coil version of Podkletnov's apparatus works. A diagram of the coil arrangement is shown below. Only one of the coils is shown in the diagram. The second coil is a mirror image of the first on the right side of the disc. From EE Podkletnov, arxiv, (1997), http://arxiv.org/abs/cond-mat/9701074 The magnetic field, (B coil), created by the coil will be parallel to the surface of the superconducting disc. Via the Meissner effect, supercurrents will be setup in the superconductor that are parallel to the coil windings, but in the opposite direction. These supercurrents are at right angles to the magnetic field that originally created them. The magnetic field, (B supercurrent), setup by the supercurrents opposes the magnetic field in the rotation coil, (see figure below). If the two rotation coils are driven by alternating currents that are 180 degrees out of phase, then the opposing magnetic fields setup by the superc...

One of the interesting aspects of the project so far has been determining how to model the rotation of the superconducting disc in the Podkletnov apparatus. The variety of rotation coils described by Podkletnov has made the task somewhat more difficult. One of the early thoughts was that the superconductor rotated due to eddy currents created by the two-phase magnetic fields created by the rotation coils. The first video below shows a similar rotation of a normal conducting 'egg' in the presence of a rotating magnetic field created by a three-phase toroid. The next video explains the physics behind the apparatus around the time 23:35. Apparatus Demonstration: MIT Tech TV Apparatus Explanation:

One of the first tasks in this project has been to determine what the Podkletnov apparatus should do when it is operated and what physical mechanisms account for each aspect of the operation. In Dr. Podkletnov's papers, he points out that the disc is rotated with the use of solenoids that are placed around the superconducting disc in a number of configurations as shown below. I'll compare these configurations to other existing superconductor motor research in a future entry. From EE Podkletnov, arxiv, (1997), http://arxiv.org/abs/cond-mat/9701074 The above diagram shows the two phase coils that are wrapped through the disc. The magnetic field inside these solenoids will be parallel to the surface of the disc. The dashed circles indicate the levitation solenoids that lie below the disc. The next diagram is a detail of one of the through wrapped solenoids as well as a second solenoid configuration in which the solenoid windings are bent out of the way of the disc. To...