Curt Foltz     Assistant Professor, Physics & Physical Science   office:  Sci.159       foltzc@marshall.edu      (304) 696-2519

Construction – type Projects

• Fabricate a michelson interferometer inside a vacuum chamber, to measure the refractive index of B and E fields.
  Last time I tried this, the interferometer arms were only ½ meter long (1m path) with only 0.2m path length in the field.
  My laser is now about 20× more stable − good to about 15 parts per billion − so new arms will be 4.9m long,
  with 9.8m path length ... length in the field will increase to 2.8m . My new photodetectors are about 8× more sensitive than last time,
  so I'm hoping to get 1½ digits rather than just barely noticing an effect (or not)
• Spin-Orient an Electron-beam …
  Will use High Vacuum techniques and High Voltage techniques. Essentially a Stern-Gerlach magnetic field (with vertical strength-gradient)
  but crossed with an Electric field having a similar vertical strength-gradient so their Forces cancel ... except for the electron's magnetic moment along the B-field gradient.
  ... (unless the E-field is able to induce an electric dipole moment in the “point-like” electron…)
• Plasma container, and RF/microwave heater ...
  The magnetic bottle isn't too tricky, unless you want to contain neutral plasmas. (It would be nice to have a working Turbo pump by the time we test this out ...)

Measurement – type Projects

• Meta-material with negative or less-than-1 Refractive Index for Microwaves …
  Cleverly-designed conducting loops induce waves with peculiar phase relationship relative to the original. These can simulate small (or negative) refractive index … in some aspects.
  Which aspects? Consistently?
• Capture a cloud of (evaporated) sodium atoms …
  It's trickier than it looks, that's why NOT everybody has one. Measure the (trapped) lattice occupations/vacancies, and the Na spin distributions.
  Measure Ionization fraction, KE distribution (approach to equilibrium) ; can we distinguish the isotopes?

Computation / Analysis – type Projects

• Data-mining : star proper motion and v2 to map galactic disk potential function …
  If the “dark matter” resides in the halo (rather than only in the disk), oscillation periods across the disk have to be much longer than we used to expect, and out-of-plane velocity components must be quite small. Wait – they’re not … how small should they be?
  Is the data good enough to see the out-of-plane velocity component being slower, where far from the plane? If the data is high-enough quality, we can get implications on spiral-arm “density waves”.

Theory – type Projects

• Approximate Solutions to Trajectory differential Equations
  The trajectory of fast-moving objects, as they are deflected by a 1/r2 Force, can be treated exactly (hyperbolic curve). The impulse approximation treats the Force as occurring at the extrapolated distance of closest approach (rather than the slightly different real distance) for a duration that ignores the change in speed (due to the change in PE) – yet it yields the correct result! This project is to investigate why … to solve slightly different situations in exact form and in impulse approximation – to see whether it is a coincidence of 1/r2.000 , of ½mv2.000 , of being faster but closer , of projectile mass being positive , … .