The new switches for FF-2B have now been ordered and are expected to arrive in early November. The switches are a product of a long design process by LPPFusion Chief Scientist Eric Lerner, Mechanical Engineer Rudy Fritsch and Research Scientist Syed Hassan. They are critical to the experiment being planned for late this year.
The biggest differences between the new switches and the existing switches are their number and size. Instead of one switch per capacitor as in the old design, we will now have two switches, a total of 24. And of course, each switch will be about half as big. This will create a significant boost in current. As more faucets can carry more water, so can more switches carry greater current.
Fig. 1 LPPFusion’s new dual switch design, ready to be manufactured. The switches attach to a single capacitor head (not shown) below and are triggered by cable (also not shown) attached to the top of the spark plugs.
More technically, doubling the number of switches will reduce the inductance of the circuit. Inductance is a measure of how much magnetic energy a given amount of current produces. With less magnetic energy wasted in the switches, more current can be delivered and more energy transferred to the tiny plasmoid where fusion reactions take place. The switches will be a big step in getting to our full goal of doubling current from 1.2 MA to 2.4 MA.
In addition, the switches will allow a faster rise time to the pulse, which we expect will make the oscillations in the current less important. Reducing these oscillations is critical to getting good compression and high density in the plasmoid for a fast fusion burn and high yield. The switch designs include a number of improvements that will increase their reliability and reduce maintenance, an essential goal when doubling the total number of switches.
The design of the switches was made easier and more accurate by the major software and hardware upgrades undertaken by Karamitsos (see June report). Our new project data management system allowed the team to catch a number of small errors and figure out some improvements before the parts were finally approved for manufacture.