How X-rays Work" X-rays are basically the same thing as visible light rays. Both are wavelike forms of electromagnetic energy carried by particles called photons (see How Light Works for details). Ablation. Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. Examples of ablative materials are described below, and include spacecraft material for ascent and atmospheric reentry, ice and snow in glaciology, biological tissues in medicine, and passive fire protection materials.
Nuclear Fission Basics. The debate over nuclear power plants has been going on for some time, with nuclear physicists and lawmakers alike throwing around terms like nuclear fission, critical mass, and chain reaction. But how does nuclear fission work, exactly? In the 1930s, scientists discovered that some nuclear reactions can be initiated and controlled. Scientists usually accomplished this task by bombarding a large isotope with a second, smaller one — commonly a neutron. The collision caused the larger isotope to break apart into two or more elements, which is called nuclear fission. How does fission work? Ryan, It's not so much the kinetic energy of the neutron - but the fact that it is falling into a nuclear potential well. Imagine you had an old well - the type people used to haul water up from in a bucket. Except this well is dry - it's just a very deep hole in the ground lined with stones.
Now suppose you have a rock sitting on the side of the well - and you lightly push it off into the well. You didn't put much energy into the rock. How do nuclear fusion and nuclear fission work. Compton Scattering. In Compton scattering, an incoming photon of energy E (shown in black) undergoes an elastic collision with a weakly bound (assumed free) outer-shell electron (shown in blue).
Electrons, photons, and the photo-electric effect. We're now starting to talk about quantum mechanics, the physics of the very small.
Planck's constant. Plasmas. Plasmas exist in a wide range of settings and varieties.
Most stars are made up of plasma. The Aurora Borealis is a plasma light show in our upper atmosphere caused by the bombardment from space of the solar wind - another kind of plasma. Lightning bolts are visible plasma trails left by the passage of the electric current that formed it. As stated in the definition, plasma is a gaseous type of state where the matter making the plasma consists of electrically neutral and charged particles. Overall, plasma is electrically neutral having as many positive ions as free electrons distributed through it. Accelerating electrons through ordinary gas can create plasma, in just the way they create lightning.
New Cold Fusion Evidence Reignites Hot Debate. 25 March 2009—On Monday, scientists at the American Chemical Society (ACS) meeting in Salt Lake City announced a series of experimental results that they argue confirms controversial ”cold fusion” claims.
Chief among the findings was new evidence presented by U.S. National Ignition Facility. The National Ignition Facility, located at Lawrence Livermore National Laboratory.
The target assembly for NIF's first integrated ignition experiment is mounted in the cryogenic target positioning system, or cryoTARPOS. The two triangle-shaped arms form a shroud around the cold target to protect it until they open five seconds before a shot. National Ignition Facility & Photon Science - Bringing Star Power to Earth. Scientists plan to ignite tiny man-made star. How scientists brought the power of the Sun to Earth « Goodheart's Extreme Science. Fusion power. 106, 085004 (2011): Demonstration of Ignition Radiation Temperatures in Indirect-Drive Inertial Confinement Fusion Hohlraums. Big science in a small space. The National Ignition Facility (NIF) at Lawrence Livermore in California was designed with a specific goal: to use high-powered lasers to ignite a fusion reaction that releases more energy than the one million joules needed to start it.
Now, in a pair of papers appearing in Physical Review Letters (Kline et al. and Glenzer et al.), scientists at NIF are reporting some of the first tests at the new facility. In experiments that simulate “real” conditions more closely than any previous attempt, the team shows they are able to successfully generate the almost sunlike levels of heat needed for laser-driven fusion. The planned target of NIF’s lasers is a pill-sized hollow gold target, called a hohlraum, that encases a “fusion capsule”—about micrograms of solid deuterium-tritium mix, surrounded by a light material. As a test, the NIF team used plastic capsules filled with helium instead of nuclear fuel. Nuclear Fusion : WNA. (Updated February 2014) Fusion power offers the prospect of an almost inexhaustible source of energy for future generations, but it also presents so far insurmountable scientific and engineering challenges.
The main hope is centred on tokamak reactors which confine a deuterium-tritium plasma magnetically. Today, many countries take part in fusion research to some extent, led by the European Union, the USA, Russia and Japan, with vigorous programs also underway in China, Brazil, Canada, and Korea. Initially, fusion research in the USA and USSR was linked to atomic weapons development, and it remained classified until the 1958 Atoms for Peace conference in Geneva.