BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:"Chasing Dynamos with Confined and Unmagnetized Flowing Plasma"
DTSTART:20150129T150000
DTEND:20150129T160000
DTSTAMP:20260510T101056Z
UID:a071301da2e63b0562ea7aea7321acba85aad26a23049723e9dd341a
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Cary Forest (Univ. of Wisconsin\, Madison\, USA)\nThe Ma
 dison Plasma Dynamo Experiment (the MPDX) a 3 meter diameter spherical vac
 uum vessel that uses an array of 3000 4 kG samarium cobalt permanent magne
 ts in a 36 ring ring cusp arrangement\, and ~200kWs of LaB6 hot cathode po
 wer to ionize and heat  plasma\; this is now generating a steady-state\, 
 hot (20eV) plasma with densities of 1018m-3. The cathodes also can stir th
 e unmagnetized core plasma at speeds of up to 12km/s through J´B torque a
 t the magnetized edge of He plasmas. Laminar counter-rotating two-vortex f
 lows\, are  predicted to have a critical threshold of spontaneous creatio
 n of magnetic field that depends upon the magnetic Reynoµlds number Rm=m0
 sLV\, a dimensionless triple product that must exceed 250 for self-excitat
 ion. Hence the electron confinement plays a critical role in governing the
  dynamo onset. Two dimensional VPIC simulations of density\, temperature a
 nd wall losses to the dipole magnet rings are compared directly to measure
 ments of 2D plasma profiles and measured confinement times. The fluid Reyn
 olds number\, depends largely upon density\, the ion temperature and the e
 ffective charge\, scaling ReµL V Z4 n/Ti5/2\; hence ion heating and confi
 nement are also important. To study the hydrodynamic turbulence requires h
 igh density and low ion temperature (and/or multiply charged ions). So far
 \, MPDX has achieved Rm»300 and Re»200 which is nearly optimal for obser
 ving a laminar dynamo.  Fast turbulent dynamos seem feasible give the con
 finement scaling projections based upon the experimental parameters.
LOCATION:PPB 019
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR