Linear transformer driver

A linear transformer driver (LTD) is an annular parallel connection of switches and capacitors designed to deliver rapid high power pulses. The LTD was designed at the Institute of High Current Electronics (IHCE) in Tomsk, Russia. The LTD is capable of producing high current, up to 1 megaamp (10⁶ amps), pulses with a risetime of less than 100 ns. This is an improvement over Marx generator based pulsed power devices which require pulse compression to achieve such fast risetimes. It is being considered as a driver for z-pinch based inertial confinement fusion.

LTDs at Sandia National Laboratories

Sandia National Laboratory is currently investigating a z-pinch as a possible ignition source for inertial confinement fusion. On its "Z machine", Sandia can achieve dense, high temperature plasmas by firing fast, 100-nanosecond current pulses exceeding 20 million amps through hundreds of tungsten wires with diameters on the order of tens of micrometres. The LTD is currently being investigated as a driver for the next generation of high power accelerators.

Sandia's roadmap includes another future Z machine version called ZN (Z Neutron) to test higher yields in fusion power and automation systems. ZN is planned to give between 20 and 30 MJ of hydrogen fusion power with a shot per hour thanks to Russian Linear Transformer Driver (LTD) replacing the current Marx generators.^[1] After 8 to 10 years of operation, ZN would become a transmutation pilot plant capable of a fusion shot every 100 seconds.^[2]

The next step planned would be the Z-IFE (Z-inertial fusion energy) test facility, the first true z-pinch driven prototype fusion power plant. It is suggested it would integrate Sandia's latest designs using LTDs. Sandia labs recently proposed a conceptual 1 petawatt (10¹⁵ watts) LTD Z-pinch power plant, where the electric discharge would reach 70 million amperes.^[3]

Proposed model of a 1,000 terawatt LTD-based z-pinch accelerator.
104 m diameter, 70 million amperes, 24 megavolts.
Human being (the black line just left of the center of the LTD) for scale.

External links

• Development and tests of fast 1-MA linear transformer driver stages
• http://www.sandia.gov/news/resources/releases/2007/rapid-fire-pulse.html
• http://www-ners.engin.umich.edu/labs/plasma/Research/ZPinch.html

Notes and references

1. Rapid-fire pulse brings Sandia’s Z method closer to goal of developing high-yield fusion reactor, Sandia's press release (April 27 , 2007).
2. Z-Inertial Fusion Energy: Power Plant Final Report FY 2006, Sandia Report SAND2006-7148 (October 2006).
3. W.A. Stygar et al., Architecture of petawatt-class z-pinch accelerators (October 2007).