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The current popular technical paradigm insists high resonator quality factor Q, and by implication high frequency operation, is essential for efficient power transmission by means of resonant induction. This paper examines the theoretical argument and the experimental evidence against the current paradigm. It shows high frequency operation has few, if any, operational advantages and indeed has several...
It is the presumption of many that wireless power transmission (WPT) systems are inherently unsafe because they produce time-varying magnetic fields. While it is true that there are limits to human exposure, the safety issues are actually well understood and pose more of a public (or consumer) perception challenge than a real health risk when operated in the context of modern WPT vehicle systems....
Today, adopters of high power wireless chargers are faced with a dilemma: is the appropriate figure of merit kQ or kra? Wireless Power Transfer, WPT, throughput power is generally taken as the product of the high frequency inverter kVA rating multiplied by a function of kQ, with emphasis on high Q. On the other hand, an optimal matching condition relies on kra, which provides a guide to matching to...
In the present research, collimated plasma jets form from Joule heating and ablation of a radial foil (Al 20 μm thin disk) using a pulsed power generator (COBRA) with 1 MA peak current and 100 ns rise time. Plasma dynamics of the jet are diagnosed with and without an applied uniform external magnetic field (∼1 T axial Bz) and under a change of current polarities, which correspond to current moving...
This research focuses on the initial ablation phase of a thin (20μm) Al foil driven on the 1MA-in-100ns COBRA through a 5mm diameter cathode in a radial configuration. In these experiments, ablated surface plasma (ASP) on the top side of the foil and a strongly-collimated axial plasma jet can be observed developing midway through current-rise. Our goal is to establish the relationship between the...
Previous investigations of exploding radial foils have shown the formation of a dense highly-collimated hypersonic axial plasma jet in the early stages of the foil explosion. In this case a thin load foil is pressed at an outer annulus held at ground, and contacted in the center by a small straight rod cathode driven by a 1MA-in-100ns pulse from COBRA. Recent experiments focus on the initial jet development...
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