Wednesday, January 19, 2011

Focus Fusion Reaches One Billion degree Benchmark

Focus Fusion has had a paper accepted for publication that confirms that they have achieved a key milestone of 100keV.  The work itself was delayed months in order to produce more robust switching equipment.

The present anticipated time table targets a successful test during the coming year, although equipment issues can obviously arise anytime.  This is true for all development of course.

What is important for now is that this is in the bag and it will be published.

JANUARY 11, 2011

The article is particularly significant as the first peer-reviewed publication of the basic theory guiding LPP's pursuit of useful fusion energy from the dense plasma focus, as well as featuring the first experimental results from the team's Focus Fusion-1 experimental device

JANUARY 04, 2011


In a breakthrough in the effort to achieve controlled fusion energy, a research team at Lawrenceville Plasma Physics, Inc. (LPP) in Middlesex, NJ, announced that they have demonstrated the confinement of ions with energies in excess of 100 keV (the equivalent of a temperature of over 1 billion degrees C) in a dense plasma. They achieved this using a compact fusion device called a dense plasma focus (DPF), which fits into a small room and confines the plasma with powerful magnetic fields produced by the currents in the plasma itself. Reaching energies over 100 keV is important in achieving a long-sought goal of fusion research—to burn hydrogen-boron fuel. Hydrogen-boron, (also known by its technical abbreviation, pB11) is considered the ideal fusion fuel, since it produces energy in the form of charged particles that can be directly converted to electricity. This could dramatically cut the cost of electricity generation and eliminate all production of radioactive waste.

The dense plasma focus has been studied for over 40 years. However, LPP has been able to make great strides since its ―Focus-Fusion-1 experimental device started producing data in October, 2009, due to its unique, patented design. Most importantly, its electrodes, which produce the self-pinching action that concentrates the plasma and current, are much smaller than those of other DPF devices with similar peak currents. The electrode assembly is only 4 inches across and less than 6 inches in length.

The fusion energy yields achieved in these experiments are still far less than the energy used to run the machines. However, LPP hopes to make rapid progress in the coming year when the machine will be running with hydrogen–boron fuel for the first time.

Previous experiments by LPP and other researchers had observed the high-energy ions, and had obtained evidence that they are confined in dense hot spots of plasma, called plasmoids. But they could not rule out an alternative hypothesis—that the fusion reactions observed were due to a beam of ions cruising unconfined through the diffuse background gas in the vacuum chamber of the experiment. This question is critical to the viability of the DPF as a fusion generator, because only if some ions are trapped, circulating around and around within a dense plasmoid, can they heat the fuel up sufficiently to ignite a self-sustaining burn that will consume most of the fuel in the plasmoids. A diffuse beam alone, traveling on a one-way trip through cold and much less-dense background plasma, will not be able to do that.

The new research at LPP’s Middlesex laboratory has now ruled out this beam-only hypothesis by clearly showing that the ions are confined. This conclusion is based on a combination of evidence from several experiments and instruments, obtained over the past nine months, which fit together like pieces of a jig-saw puzzle. The detailed scientific results are being submitted for publication in Physical Review Letters, a leading physics journal.

The evidence for ions with energies more than 100 keV was obtained in three experiments in late September and late October, and were replicated this week. These experiments used deuterium, a heavy isotope of hydrogen, as the fuel, as is standard in most fusion experiments. Researchers observed the neutrons emitted from fusion reactions occurring when the deuterium ions collided with each other. By measuring the difference in the neutron arrival times at two detectors set at different distances—11 meters and 17 meters—from the axis of the fusion device, the physicists could calculate the energy of the ions that produced them. The greater the spread in the neutrons’ arrival times, the greater their range of velocities and thus the greater the range of velocities of the deuterium ions that fused to produce the neutrons. More velocity means more energy, so this is a measure of the ions’ energy. (See Figure 1.) Eric J. Lerner, LPP’s president and lead scientist, explains, ―In our best shot, on September 29, we calculate the average ion energy at between 160 and 220 keV, so we feel confident in conservatively saying that ion energies are above 100 keV.

Three other shots also exceeded 100 keV (the most recent on January 3, 2011), and these were the upper end of a continuous distribution of ion energies in many other shots, not extreme outliers.

DECEMBER 22, 2010

It is shown that in contrast to the electric pulse power driven implosion of a single conical wire array, the implosion of a nested conical wire array with opposite alternate opening angles can lead to the generation of fast jets, with velocities of the order 10^8 cm/s. This technique can be applied for the supersonic shear flow stabilization of a dense z-pinch, but possibly also for the fast ignition of a pre-compressed dense deuterium-tritium target.

Back in 1967, Winterberg had proposed to reach very large jet velocities by the impact under a small angle of a projectile on a stationary solid target. For impact velocities of ~10^7 cm/s and an angle of less than 10 degrees, jet velocities of the order 10^8 cm/s could be expected, as they are needed for impact fusion. Projectile velocities of ~10^7 cm/s can in principle be reached by the acceleration of a small superconductingsolenoid with a magnetic travelling wave accelerator, but the length of such an accelerator was estimated to be of the order 10 km. However, it has been shown that such velocities can also be reached over a distance of a few cm by the electric pulse power driven implosion of a cylindrical thin wire array. This raises the question if with this technique jet velocities of the order 108 cm/s can be reached by the implosion of a conical wire array with a small opening angle. It turns out that this is not possible, but possible with a nested conical wire array.

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