The CV apparatus was constructed for experiments on plasmas of a single species. Using ultra-high vacuums ( 2 x 10-11 torr ) and Cryogenics, CV can sustain pure-electron plasmas of temperature ranging from 25 to 2 x 106 . The trap is a Penning-Malmberg trap in which the plasma is contained radially by a magnetic field of strength 20 to 20K Gauss, and contained axially by an electrostatic field. Plasma is created and initially caught at a temperature of 104. Plasma can then by heated by axial compression and relaxation (which heats since the process is non-adiabatic), and naturally cools due to cyclotron-radiation.


here diagram of CV

Like with the CamV and EV experiments, measurement of the plasma in CV is a destructive process requiring dumping of the plasma. This dumping is accomplished by ramping the negative potential on one of the end cylindrical electrodes to zero. The plasma flows out along the magnetic field lines onto a series of charge collection plates.

RESULTS FROM CV

These are some of the most significant results from the CV apparatus. For a more detailed explanation of experiments and results, volumes University of California San Dieogo Physics Review Letters are available on request. The volume number(s) in which the relevant paper(s) was first published are included in the summary of results shows below.


ANISTROPIC TEMPERATURE RELAXATION RATE IN A PURE ELECTRON PLASMA

Heating of our plasmas is accomplished by compressing and relaxing the plasma by sinusoidally modulation the potential on the confining electrode. This work against the axial kinetic and electrostatic pressures is irreversiable due to collisions. The work done on the plasma, and thus the heating rate, is greatest when the frequency of compression cycles matches the relaxation frequency of the plasma.

*
B.R. Beck, J. Fajans and J.H. Malmberg, "Temperature and Anisotropic-Temperature Relaxation Measurements in Cold, Pure-Electron Plasmas," Phys. Plasmas 3, 1250 (1996).




TRANSPORT AND SAWTOOTH OSCILLATIONS IN A PURE ELECTRON PLASMA

Sawtooth oscillations occur at low temperatures (below .02 eV). At these low temperatures, any small drop in the temperature decreases the heating rate more than the cooling rate causing a cooling of the plasma untill it reaches a minimum temperature set by joule-heating due to background transport. However, this cooling also decreases the dampening rate, which then allows the displacement of the plasma to grow untill the heating rate is once again greater than the cooling rate. The plasma then heats to a new quasi-stable equalibrium.

*
B.P. Cluggish, C.F. Driscoll, K. Avinash and J.A. Helffrich, "Sawtooth Oscillations in A Damped/Driven Cryogenic Electron Plasma: Experiment and Theory," Phys. Plasmas 4, 2062 (1997).




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