A post submitted by CGI member ScienceTruth.

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https://youtu.be/Icq8yBxDMLw

The Winnemucca Institute for Advanced Studies presents

The ElectroMagnetic Z-Pinch

The Bennett Pinch, also known as a Z-Pinch, is where a large electric current is induced to flow in a confined plasma, which then causes a magnetic field to suddenly manifest. The power of the magnetic field will influence the ionized plasma to 'contract together' unto itself very rapidly and tightly. Thus the Pinch term. The Bennett Pinch is named after him, but it was later re-termed the Z-Pinch to describe a more accurate physical description of the action involved. The Z-pinch is an application of the Lorentz force, in which a current-carrying conductor in a magnetic field experiences a force. One example of the Lorentz force is that, if two parallel wires are carrying current in the same direction, the wires will be pulled toward each other. In a Z-pinch machine the wires are replaced by a plasma, which can be thought of as many current-carrying wires. When a strong electric current is run through the plasma, the particles in the plasma are pulled together by the Lorentz force, thus the plasma contracts. As plasma is electrically conductive, a magnetic field nearby may induce a current in it. This provides a way to run a current into the plasma without physical contact, which is important as a plasma can rapidly erode mechanical electrodes.

Willard Harrison Bennett

Willard Harrison Bennett (June 13, 1903 – September 28, 1987) an American scientist and inventor was born in Findlay, Ohio. Bennett conducted research into plasma physics, astrophysics, geophysics, surface physics, and physical chemistry.

Bennett attended Carnegie Institute of Technology from 1920 to 1922, also Ohio State University, the University of Wisconsin for a Sc.M. (Master's Degree in Science subjects) in physical chemistry in 1926, and the University of Michigan for a Ph.D. in Physics in1928. Bennett was elected to a National Research Fellowship in Physics and in 1928 and 1929 studied at the California Institute of Technology. In 1930 he joined the Physics faculty at Ohio State. During the World War II era, he served as an officer in the United States Army and developed aircraft equipment. Following military service, Bennett worked at the National Bureau of Standards, the University of Arkansas, and the United States Naval Research Laboratory. In 1961, he was appointed Burlington Professor of Physics at North Carolina State University (Emeritus in 1976). Bennett held 67 Patents.

Bennett made scientific history in the 1930's pioneering studies in plasma physics, the study of gases ionized by high-voltage electricity. Bennett invented the radio frequency mass spectrometry concept in 1955. Bennett's radio-frequency mass spectrometer measured the masses of atoms, and was the first such experiment done in Space.. He researched gases ionized by high-voltage electricity. This research was used in later thermonuclear fusion research.

These studies and later research have been used throughout the world in controlled thermonuclear fusion research. In the 1950's, Bennett's experimental tube called the Stormertron predicted and modeled the Van Allen radiation belts surrounding the Earth six years before they were discovered by satellite. It also reproduced intricate impact patterns found on the Earth's surface which explained many features of the polar aurora. Sputnik 3 carried the first radio frequency mass spectrometer into space to measure the masses of atoms.

In atomic fusion power theory research, the Z-pinch is a type of plasma confinement system that uses an electric current in the plasma to generate a magnetic field that compresses it. These systems were originally referred to simply as a pinch, or a Bennett Pinch, but the introduction of the θ-pinch (theta pinch) concept led to the need for clearer, more precise terminology.

The Z-Pinch name refers to the direction of the current in the device, the Z-Axis on a Cartesian three-dimensional graph, as Bennett initially had his glass confinement tube for the plasma mounted in a vertical position, the Z-Axis. Any machine that causes a pinch effect due to current running in a plasma since then, is termed a Z-pinch, and this encompasses a wide variety of devices used for an equally wide variety of purposes. Early uses focused on fusion research in donut-shaped tubes with the Z-axis running along the inside-center-line of the tube, while modern devices are generally cylindrical and used to generate high-intensity x-ray sources for the study of nuclear weapons and other roles, the term Z-Pinch is ubiquitous to them all. This is one of the first approaches to fusion power devices, along with the stellarator and magnetic mirror.

The Z-pinch is an application of the Lorentz force, in which a current-carrying conductor in a magnetic field experiences a force. One example of the Lorentz force is that, if two parallel wires are carrying current in the same direction, the wires will be pulled toward each other. In a Z-pinch machine the wires are replaced by a plasma, which can be thought of as many current-carrying wires. When a strong electric current is run through the plasma, the particles in the plasma are pulled together by the Lorentz force, thus the plasma contracts. The contraction is then counteracted by the increasing gas pressure of the plasma atoms itself, and so a limit to the contraction is maintained, based on the amount of the current flow supplied.

As plasma is electrically conductive, a magnetic field nearby may induce a current in it. This provides a way to run a current into the plasma without physical contact, which is important as a plasma can rapidly erode mechanical electrodes. In practical devices this was normally arranged by placing the plasma vessel inside the core of a transformer, arranged so the plasma itself would be the 'secondary'. When current was sent into the 'primary' side of the transformer, the magnetic field induced a current into the plasma. As induction requires a changing magnetic field, and the induced current is supposed to run in a single direction in most reactor designs, the current in the transformer has to be increased over time to produce the varying magnetic field. This places a limit on the product of confinement time and magnetic field, for any given source of power.

In Z-pinch machines the current is generally provided from a large bank of capacitors and triggered by a spark gap, known as a Marx Bank or Marx generator. As the conductivity of plasma is fairly good, about that of copper, the energy stored in the power source is quickly depleted by running through the plasma. Z-pinch devices therefore are inherently pulsed in nature due to the huge demand for current flow, and the capacitor bank's lack of practical capacity for any sustained supply, thus the pulsed nature of the experiment.

NIHF Inductee Willard Bennett and Radio Frequency Spectrometer. www.invent.org

Bennett, Willard H. "Magnetically Self-Focusing Streams". Physical Review. 45 (12)

Willard Harrison Bennett National Inventors Hall of Fame materials, 1990-1991 NC State University Libraries Collection Guides

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Wikipedia provided the bulk of the above 'biographies', but I did take many liberties in editing and rearranging their text. Also a couple of other sites provided contributions of reference data and other items.

Information provided herein by the Winnemucca Institute for Advanced Studies is for educational purposes. Our ‘Man on the Street Series’ of informative Science Papers is designed to provide a semi-technical answer to everyday experiences.

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This is a 'repeat' of last week's posting, the Part 2 Section anyway. As the first part about Irving Langmuir was so long-winded, I began to think many readers may have 'given up' and didn't get to the 2nd part ! So, decided to post Part 2 of last week's posting this week ! As understanding the Z-Pinch is very important !!!

Apologies if you did read this last week. New Topics will resume next week with Electric Double Layers, and then Marklund Convection.