Lichtenberg figures are named after the German physicist Georg Christoph Lichtenberg, who originally discovered and studied them. Lichtenberg Figures are typically formed by the rapid electric discharge or redistribution of charge carriers residing on the surface or the interior of nonconductors. When first discovered it was thought that their characteristic shapes might help to reveal the nature of positive and negative electric "fluids". Georg Christoph Lichtenberg is a 18th-century German scientist, satirist and anglophile, most famous for his notebooks published posthumously (which he himself called waste books, using the English bookkeeping term). ... a localised surplus of electrons migrates from the negative pole to the positive pole to overcome its unfavourable energetic condition. ... Charge carrier denotes in physics a free (mobile, unbound) particle carrying an electric charge. ... Nonconductors or electrical insulators are materials which lack movable electric charges, and which therefore lack a low-resistance path for charge flow. ...

Formation

One way that they can be produced is as follows: A sharp-pointed needle is placed perpendicular to a non-conducting plate, such as of resin, ebonite, or glass, with its point very near to or in contact with the plate, and a high voltage Leyden jar (a type of capacitor) or a static electricity generator is discharged into the needle. The electrification of the plate is now tested by sifting over it a mixture of powdered flowers of sulfur and red lead (Pb₃O₄ or lead tetroxide). Insect trapped in resin. ... Ebonite is one of the earliest forms of plastic. ... This article refers to the material. ... Original capacitor The Leyden jar was the original capacitor, developed in the 18th century and used to conduct many early experiments in electricity. ... A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... Static electricity is a class of phenomena involving the net charge present on an object; typically referring to charged object with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... Red lead, also called minium or lead tetroxide, is a bright red or orange crystalline or amorphous pigment. ...

The negatively electrified sulfur is seen to attach itself to the positively electrified parts of the plate, and the positively electrified red lead to the negatively electrified parts. In addition to the distribution of color thereby produced, there is a marked difference in the form of the figure, according to the polarity of the electrical charge that was applied to the plate. If the charge was positive, a widely extending patch is seen on the plate, consisting of a dense nucleus, from which branches radiate in all directions; if negative, the patch is much smaller and has a sharp circular boundary entirely devoid of branches.

If the plate receives a mixed charge, as, for example, from an induction coil, a mixed figure results, consisting of a large red central nucleus, corresponding to the negative charge, surrounded by yellow rays, corresponding to the positive charge. The difference between the positive and negative figures seems to depend on the presence of the air; for the difference tends to disappear when the experiment is conducted in vacuo. Riess explains it by the negative electrification of the plate caused by the friction of the water vapour, etc., driven along the surface by the explosion which accompanies the disruptive discharge at the point. This electrification would favor the spread of a positive, but hinder that of a negative discharge. Lichtenberg figures are fully described in two memoirs Super nova methodo naturam ac motum fluidi electrici investigandi (Göttingen, 1777-1778). An induction coil (archaically known as a Ruhmkorff coil) is a type of disruptive discharge coil. ... Look up air in Wiktionary, the free dictionary. ... Look up Vacuum in Wiktionary, the free dictionary For other uses, see vacuum (disambiguation) A vacuum is a volume of space that is empty of matter, including air, so that gaseous pressure is much less than standard atmospheric pressure. ... A Disruptive discharge is the result of a dielectric being stressed beyond its dielectric strength. ...

Modern 3D Lichtenberg Figure in a block of clear acrylic. The fractal discharge pattern is believed to extend down to the molecular level. Actual size: 3" x 3" x 2".

Download high resolution version (1000x908, 258 KB)3-D Lichtenberg Figure in Acrylic This 3 x 3 x 2 three dimensional Lichtenberg Figure was created by ebeam irradiation along multiple planes. ... Download high resolution version (1000x908, 258 KB)3-D Lichtenberg Figure in Acrylic This 3 x 3 x 2 three dimensional Lichtenberg Figure was created by ebeam irradiation along multiple planes. ...

Modern Lichtenberg Figures

Modern Lichtenberg Figures can also be created within solid blocks of acrylic plastic (polymethyl methacrylate or PMMA) using a beam of electrons from a linear electron beam accelerator (or Linac, a type of particle accelerator). Inside the Linac, electrons are focused and accelerated to form a beam of high speed particles. Electrons emerging from the accelerator are moving an appreciable fraction (95 - 99+ percent) of the speed of light (relativistic velocities). The electron beam is then aimed towards an acrylic specimen. When the relativistic electrons hit the acrylic, they easily penetrate the surface, slowing down as they collide with the molecules inside the plastic, and finally coming to rest deep inside the specimen. Since acrylic is an excellent electrical insulator, the electrons inside the specimen are temporarily trapped. Under continued irradiation by the beam, the excess electrons form a plane of negative charge inside the specimen. As the charge builds, the effective voltage inside the specimen can reach millions of volts. Ultimately the huge electrical stress exceeds the dielectric strength of the plastic, causing it to suddenly become conductive in a process called dielectric breakdown. Structure of PMMA: (C5O2H8)n Structure of methyl methacrylate Polymethyl methacrylate (PMMA) or polymethyl-2-methylpropanoate is the synthetic polymer of methyl methacrylate. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A linear particle accelerator is an electrical device for the acceleration of subatomic particles. ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A particle accelerator is a device that uses electric and/or magnetic fields to propel electrically charged particles to high speeds. ... Cherenkov effect in a swimming pool nuclear reactor. ... Albert Einsteins theory of relativity is a set of two theories in physics: special relativity and general relativity. ... // Definition An Insulator is a material or object which resists the flow of electric charge. ... In physics, the term dielectric strength has the following meanings: Of an insulating material, the maximum electric field strength that it can withstand intrinsically without breaking down, , without experiencing failure of its insulating properties. ...

Once breakdown occurs, branching tree or fern-like conductive channels are rapidly formed within the plastic, allowing the trapped charge to suddenly rush out in a miniature lightning-like flash and bang. Electrical breakdown of a charged specimen may also be manually triggered by poking the plastic with a pointed conductive object. The powerful electrical spark leaves thousands of permanent branching chains of fractures behind - creating a Lichtenberg figure. Although the internal charge within the specimen is negative, the actual discharge is initiated from the positively charged exterior surfaces of the specimen, and the resulting discharge actually creates a positive Lichtenberg figure within. These rare and beautiful objects are sometimes called electron trees, beam trees, or lightning trees. As the electrons rapidly decelerate inside the acrylic, they also generate powerful X-rays. These X-rays darken the acrylic by introducing defects (color centers) in a process called solarization. Solarization turns acrylic specimens an amber or brownish color, although older acrylic blends sometimes turn a lime green. The color usually fades over time, and gentle heating, combined with oxygen, accelerates the fading process. Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. ... Look up Spark in Wiktionary, the free dictionary The word spark has several meanings: Sparks produced by grinding In electricity, spark usually refers to a momentary electrostatic discharge across a spark gap. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... Solarization is a photography term often used (incorrectly) to refer to the Sabatier Effect, in which a print is re-exposed by switching on light for a couple of seconds, halfway through the development process, causing reversal of tones in parts of the picture. ...

Natural occurrences

Lichtenberg figures may also appear on the skin of lightning victims. These are reddish, fernlike patterns that may persist for hours or days on survivors. They are also a useful indicator for medical examiners when trying to determine the cause of death in a victim. Lichtenberg figures appearing on people are sometimes called Lightning Flowers, and they are thought to be caused by the rupture of small capillaries under the skin due to either the passage of the lightning current or the shock wave from the lightning discharge. A lightning strike can also create a large Lichtenberg Figure in the grass surrounding the point hit by the bolt. These are sometimes found on golf courses or in grassy meadows. Fulgurites may also be created as sand and soil is fused into glassy tubes by the heat of the high current lightning discharge. Lightning is a powerful natural electrostatic discharge produced during a thunderstorm. ... The word capillary is used to describe any very narrow tube or channel through which a fluid can pass. ... In fluid dynamics, a shock wave is a nonlinear or discontinuous pressure wave. ... This article is about the sport of golf. ... Fulgurites (from the Latin for thunderbolt) are natural hollow carrot-shaped glass tubes formed in sandy soil by lightning strikes. ... For other uses, see Sand (disambiguation). ... Soil is material capable of supporting plant life. ...

Fractal similarities

The branching, self-similar patterns observed in Lichtenberg figures exhibit fractal properties. Lichtenberg figures often develop during the dielectric breakdown of solids, liquids, and even gases. Their appearance and growth appear to be related to a process called Diffusion Limited Aggregation or DLA. A useful macroscopic model that combines an electric field with DLA was developed by Niemeyer, Pietronero, and Weismann in 1984, and is known as the Dielectric Breakdown Model (DBM). Although the electrical breakdown mechanisms of air and PMMA are considerably different, the branching discharges turn out to be related. So, it should not be surprising that the branching forms taken by natural lightning also have fractal characteristics. A self-similar object is exactly or approximately similar to a part of itself. ... The boundary of the Mandelbrot set is a famous example of a fractal. ... The term electrical breakdown has several similar but distinctly different meanings. ... A brownian tree example A brownian tree is a form of computer art that was briefly popular in the 1990s, when home computers started to have sufficient power to simulate brownian motion. ... Dielectric Breakdown Model (DBM) is a macroscopic mathematical model combining the Diffusion Limited Aggregation model with electric field. ...

External links

Wikimedia Commons has media related to:

Lichtenberg figure

• What are Lichtenberg Figures and how are they created?
• Lichtenberg Figures, Glass and Gemstones
• 1927 General Electric Review Article about Lichtenberg Figures
• NASA article on lightning's effects on humans
• About Electricity, Lightning, and Lichtenberg Figures
• Photo of a Lichtenberg Figure on a golf course
• Photo of a Lichtenberg Figure on a man's back
• Dielectric Breakdown Model (DBM)
• Mathematical Description of Diffusion Limited Aggregation