http://pubs.acs.org/cen/coverstory/83/8348atoms.html
"The run-up to the 1955 milestone starts with Müller's invention in 1936 of the field emission microscope, which predates the field ion microscope by more than 10 years. In the field emission instrument, a specimen in the form of a sharp tip or needle is maintained under high vacuum and subjected to a large negative voltage. Applying a few thousand volts to a specimen with a tip radius of approximately 50 nm results in an electric field at the specimen tip of roughly 10 V per nm. Fields of that magnitude are strong enough to cause electrons to be emitted from the tip via quantum mechanical tunneling, a process that had been predicted by pioneers of quantum theory in the 1920s. 10 Gigavolts per meter ought to polarize any vacuum. ----- Original Message ----- From: Frederick Sparber To: [email protected] Sent: 11/19/2006 2:49:18 AM Subject: Re: The Polarized Vacuum Spacebubble Concept Can you get a high enough E-Field/Energy Density to effect enough Polarized Vacuum to create a "Spacebubble"? Cylindrical Capacitor Equations: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capcyl.html Spherical Capacitor and Isolated Sphere Capacitance Equations: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capsph.html For example an isolated 2.0 meter diameter Van de Graaff sphere (R = 1.0 meter) has a capacitance C = 4(pi)eoR = 4*3.14159*8.85E-12*1.0 = 1.112E-10 farads. If it has 3.0 million volts on it (3.0 million volts per meter is the corona onset point [the breakdown point of air at sea level pressure-temperature]) the charge Q = C*V = 1.112E-10 farad* 3E6 volts = 3.336E-4 Coulombs. Since the fundamental unit of charge (plus or minus) = 1.6E-19 Coulombs, dividing Sphere Charge Q by 1.6E-19 = 3.336E-4/1.6E-19 = 2.08E15 electrons spread over the 2.0 meter diameter sphere surface of 4(pi)R^2 meters or 4*3.14159* 1.0^2 = 1.659E14 electrons per square meter. The same exercise can be applied to a wire of a given diameter and length to see where the corona point in air sets in (76 Kilovolts/Inch radius or 3.0 Megavolts/meter radius) and the corresponding surface electron density. Vacuum Breakdown Info: http://w4.lns.cornell.edu/public/CESR/SRF/dissertations/werner/werner.html Fred
