AN INTERPRETATON OF BALL LIGHTNING
(June 2024)
ABSTRACT
Spherical lightning is not measurable, but similar atmospheric phenomena are related to the ionisation of gases: glowing embers, arc light and aurora. In air, the colours of the phenomenon are caused by ionised oxygen and nitrogen atoms. The main characteristics of corona discharge glow, which is the stationary collisional ionisation of air, also known as St Elmo's fire, and arc glow are that they are negative resistance states of the plasma: the current also increases as the voltage decreases. So there is a description and stability condition without assuming a central force field. At the negative-resistance state, the current, i.e. the number of ions, would increase at voltage decreases, if recombination did not limit it.
The atmospheric electric potential can be tens of thousands of volts per centimetre, which ionises oxygen and nitrogen in the air. The phenomenon described in the physics of lightning, that there are colored ion channels emanating from the Earth, is difficult but photographic. They are only detectable in high-speed camera images, they collapse, they are not part of cloud lightning. Ion channels from the Earth are thought to be the source of ionised oxygen and nitrogen atoms, the flowing ion clouds of the globular lightning. If the atmospheric pressure is sufficiently high, and if a sufficient number of ions have been created, the ion channel stabilises in the negative-resistance state, known as a glowing ember, or corona discharge.
The atmospheric electric potential can be tens of thousands of volts per centimetre, which ionises oxygen and nitrogen in the air. The phenomenon described in the physics of lightning, that there are colored ion channels emanating from the Earth, is difficult but photographic. They are only detectable in high-speed camera images, they collapse, they are not part of cloud lightning. Ion channels from the Earth are thought to be the source of ionised oxygen and nitrogen atoms, the flowing ion clouds of the globular lightning. If the atmospheric pressure is sufficiently high, and if a sufficient number of ions have been created, the ion channel stabilises in the negative-resistance state, known as a glowing ember, or corona discharge.
In corona discharge, the electron avalanches cause collisional ionisation, a self-excited process that creates a negative resistive state, which increases the intensity of the electron avalanches even at decreasing voltages. If the atmospheric voltage is sufficiently high, the channel becomes independent of the external voltage, another negative resistance state, characterised by thermal emission. Thermal emission increases the mobility of the electrons, the plasma starts to float freely. The negative resistance phenomenon of arc light explains the formation and stability of spherical lightning. The thermal emission is most intense in the centre of the sphere, which is one of the reasons for the inflating spherical shape, recombining the dissipating particles on its surface.
INTRODUCTION
The research tool was an internet search, a nice little video: https://www.youtube.com/watch?v=1bBNeyrMOJE). There are many explanations* of spherical lightning covering almost every topic in physics. Hypotheses that assume central force fields or rarely occurring particles are not accepted explanations.
Spherical lightning is an atmospheric phenomenon, hypothesized to be formed by ions and electrons in the air, and described by charge-discharge phenomena.
Corona discharge is a colourful, nearly spherical atmospheric ionisation phenomenon, but the source of its ions is stationary, characterised by glowing embers. It is artificially produced by needle electrodes, requires high voltage to produce, and is caused by electron avalanches. At higher voltages (the ignition voltage), the glow glow is transformed into an arc glow.
Literature review*: ball lightning is not a rare phenomenon, many unaccepted explanations have been published. For atmospheric and lightning physics, see R.P. Feynman-R.B. Leighton-M. Sands, Modern Physics, vol. 5, (p. 120, Technical Publishers, 1969. ETO 53 "19" (082)), where the authors summarize the physics of lightning in the chapter "Atmospheric Electricity". The atmospheric electric potential can be tens of thousands of volts per centimeter, which ionizes oxygen and nitrogen. The real difference in the literature hypotheses is in the quality of the charged particles and the origin of the central force fields that hold them together.
Spherical lightning is an atmospheric phenomenon, hypothesized to be formed by ions and electrons in the air, and described by charge-discharge phenomena.
Corona discharge is a colourful, nearly spherical atmospheric ionisation phenomenon, but the source of its ions is stationary, characterised by glowing embers. It is artificially produced by needle electrodes, requires high voltage to produce, and is caused by electron avalanches. At higher voltages (the ignition voltage), the glow glow is transformed into an arc glow.
Literature review*: ball lightning is not a rare phenomenon, many unaccepted explanations have been published. For atmospheric and lightning physics, see R.P. Feynman-R.B. Leighton-M. Sands, Modern Physics, vol. 5, (p. 120, Technical Publishers, 1969. ETO 53 "19" (082)), where the authors summarize the physics of lightning in the chapter "Atmospheric Electricity". The atmospheric electric potential can be tens of thousands of volts per centimeter, which ionizes oxygen and nitrogen. The real difference in the literature hypotheses is in the quality of the charged particles and the origin of the central force fields that hold them together.
In the simplest hypothesis, we have discarded the central cohesive forces. Fast electrons, the ions produced by thermal emission, cause the phenomenon of light known as coronal emission, the glowing glow. At a sufficiently high atmospheric voltage, a self-sustaining plasma is formed in a negative-resistance state, and the mobility of electrons increases with decreasing arc voltage, within the limits of energy conservation. The observed inflating spherical shape is formed as the temperature rises, with ions recombining on the surface.
The spherical shape is also caused by the skin effect (https://www.netfizika.hu/tudas/node/6218), which occurs in the plasma at high temperatures due to electron mobility in the case of a spherical filament. In thermal ionization, a radial flow occurs (max temperature at the centre and electrons are the more mobile) electrons are enriched at the surface, carrying positive ions with them, so the ion density increases radially outwards. Towards the centre, un-ionised air molecules flow in place of the ions, which - as long as the temperature and energy are sufficient - ionise.
Sources of ions: there is also a type of ion channel that is difficult to detect, originating from the Earth or from aircraft. From the "surface of the earth, especially from the prominent, mountainous parts, a zigzag flow of positive-sign electricity is also initiated in small steps towards the cloud, but never reaches the cloud. The flow from the Earth is characterised by a purplish, pinkish light, (a glowing embers, which can only be detected in high-speed camera images. In humid air, an electric field of about 100 kV/m is needed to initiate an electron avalanche). The channel from the cloud is usually white" (https://en.wikipedia.org/wiki/Lightning). The ion channel from the Earth, which is difficult to detect, collapses if it does not meet the ion channel from above, the lightning.
The known phenomenon of arc discharge, thermal emission and negative resistance explain the stability of ball lightning. The temperature of the ion cloud and the skin effect cause the spherical shape. The energy for the formation of the phenomenon is provided by the atmospheric electric potential, but the ball lightning is no longer dependent on the atmospheric potential and is macroscopically electrically neutral. Its disappearance is caused by recombination and energy conservation.
The known phenomenon of arc discharge, thermal emission and negative resistance explain the stability of ball lightning. The temperature of the ion cloud and the skin effect cause the spherical shape. The energy for the formation of the phenomenon is provided by the atmospheric electric potential, but the ball lightning is no longer dependent on the atmospheric potential and is macroscopically electrically neutral. Its disappearance is caused by recombination and energy conservation.
Description of the ball lightning: its source is the hard-to-see ion channels emanating from the surface of the earth. The ions originate from the Earth's surface, the atmospheric tension creates the channels, and they are not stable phenomena, characterised by collisional ionisation. For gas discharge, the phenomenon is called corona discharge (ember fire, St. Elmo's fire, https://en.wikipedia.org/wiki/St._Elmo%27s_fire, cold plasma) and is characterized by negative resistivity.
At sufficiently high atmospheric voltages, the ion channel is arc-light, characterized by thermal electron emission and again negative resistance (see figure below). The arc-light state is a stable phenomenon independent of the Earth's surface for a few 10 seconds, according to the laws of conservation. Lightning ion channels from the Earth or from aircraft, or possibly from other high-capacity locations, are a suitable source of ball lightning.
ABOUT THE AURORA BOREALIS
The origin of charged particles: with the solar wind, high-energy electrons and protons approach the Earth, the Earth's magnetic field directs these charged particles towards the poles, changing the direction of the particles. As the charged particles follow the magnetic lines of force into the upper atmosphere, they collide with gas atoms (mainly oxygen and nitrogen), the collisions excite the gas atoms (cold plasma), causing the gas atoms to emit light. The colour of the auroral light depends on the type of gas and the altitude at which the collisions occur, e.g. the colour of oxygen ions is different at high altitude (green) and at low altitude (yellowish, less often red).
If we match colours to temperatures and wavelengths between 1800K and 5600K degrees, then:
Colour temperatures: (https://hu.wikipedia.org/wiki/Sz%C3%ADnh%C5%91m%C3%A9rs%C3%A9klet)
THE CORONATION, ARC LIGHT
To physically model the formation of ball lightning, we use a well-known phenomenon, corona discharge, which is caused by an elusive ion channel from the Earth (https://en.wikipedia.org/wiki/Corona_discharge). Corona discharge is a local ionisation of air, and corona discharge occurs at locations where the strength of the electric field (potential gradient) exceeds the dielectric strength of the air, the latter being strongly dependent on humidity. Often visible as a bluish glow in the air (St Elmo's fire).
To physically model the formation of ball lightning, we use a well-known phenomenon, corona discharge, which is caused by an elusive ion channel from the Earth (https://en.wikipedia.org/wiki/Corona_discharge). Corona discharge is a local ionisation of air, and corona discharge occurs at locations where the strength of the electric field (potential gradient) exceeds the dielectric strength of the air, the latter being strongly dependent on humidity. Often visible as a bluish glow in the air (St Elmo's fire).
There are two types, positive and negative coronae. The physical functioning of the two types of corona discharge is fundamentally different. The reason is that the mass and mobility of the electrons and positively charged ions are substantially different. When electrons cause collisional ionisation, electron avalanches are more easily produced for large enough voltage differences. In a positive corona, all electrons move inwards into the ion cloud and ions are repelled outwards, in a negative corona the opposite is true. The light in the corona is caused by electrons recombining with positive ions to form neutral atoms, when the electron returns to its original energy level it emits photons.
At high enough atmospheric voltages, the process becomes self-excited and independent of the external voltage (negative resistance state: current is constant or increasing while voltage is decreasing or constant), which
a condition for the stability of a self-sustaining plasma.
At the ignition voltage of the air, the electrons are already sufficiently energetic to be able to emit thermal emission (https://en.wikipedia.org/wiki/Thermal_ionization), the arc flash appears. The arc-light is characterised by thermal electron emission, the plasma may contain multiple ionised atoms and its temperature increases by leaps and bounds (up to 10 000 K degrees).
Voltage-current characteristics of electrical discharge (in neon at 1 torr, with two planar electrodes separated by 50 cm).
A: random pulses by cosmic radiation
B: saturation current
C: avalanche Townsend discharge
D: self-sustained Townsend discharge
E: unstable region: corona discharge (when the voltage decreases, the current increases!)
F: sub-normal glow discharge
G: normal glow discharge
H: abnormal glow discharge
I: unstable region: glow-arc transition
J: electric arc (when the voltage decreases, the current increases!)
K: electric arc
B: saturation current
C: avalanche Townsend discharge
D: self-sustained Townsend discharge
E: unstable region: corona discharge (when the voltage decreases, the current increases!)
F: sub-normal glow discharge
G: normal glow discharge
H: abnormal glow discharge
I: unstable region: glow-arc transition
J: electric arc (when the voltage decreases, the current increases!)
K: electric arc
The A-D region is called a dark discharge; there is some ionization, but the current is below 10 microamperes and there is no significant amount of radiation produced.
The F-H region is a region of glow discharge; the plasma emits a faint glow that occupies almost all the volume of the tube; most of the light is emitted by excited neutral atoms.
The I-K region is a region of arc discharge; the plasma is concentrated in a narrow channel along the center of the tube;
a great amount of radiation is produced. (https://en.wikipedia.org/wiki/Electric_discharge_in_gases)
Wherever a small voltage drop (- Δ U) is accompanied by an increasing current Δ lg I (lg denotes a logarithm in tens), this is a "negative resistance" section of the characteristic. The first negative resistance stage is in the transition stage, where the current does not increase indefinitely because the formation of positive ions at high temperatures is an energy-intensive process. In the second negative resistance stage, the increasing current is limited only by the conservation laws.
The stability of the ball lightning for short periods (≈ a few 10 seconds) can be explained by the second negative resistance phase, when a large number of thermal electrons are formed and are kept in equilibrium by recombination. An essential step in the reasoning is the analysis of the corona discharge, which makes the phenomenon of negative resistance in the case of collisional ionization easy to interpret. Negative (differential or dynamic) resistance is a phenomenon interpreted in plasmas, semiconductors, and occurs at biased loads, i.e. it does not exist at U ≈ 0.
Voltage-current relation of electric discharge: self-sustained discharge is characterized by electron avalanches. At lower voltages, there is a glow discharge without light emission (transition phase, dark discharge), followed by an incandescent glow discharge with collisional electron avalanches (glow discharge and corona discharge: light is emitted by excited neutral atoms).
The preflash is a glow lamp, voltage decreases with increasing current, negative resistance with collisional electron conduction, an ion channel, not a ball filament. The process takes place at atmospheric pressure.
Then all charge carriers ionise by thermal emission, discharge into self-sustaining arc discharge. The contact with the ground is broken, the intensity of the flow increases.
Temperature is sufficient for thermal emission of electrons from gas molecules, inflating spherical shape above the ignition voltage, recombination of ions on the surface. This is the high temperature arc discharge stage, the warm plasma state, see video: https://www.youtube.com/watch?v=1bBNeyrMOJE.
The stability of the ball lightning for short periods (≈ a few 10 seconds) can be explained by the second negative resistance phase, when a large number of thermal electrons are formed and are kept in equilibrium by recombination. An essential step in the reasoning is the analysis of the corona discharge, which makes the phenomenon of negative resistance in the case of collisional ionization easy to interpret. Negative (differential or dynamic) resistance is a phenomenon interpreted in plasmas, semiconductors, and occurs at biased loads, i.e. it does not exist at U ≈ 0.
Voltage-current relation of electric discharge: self-sustained discharge is characterized by electron avalanches. At lower voltages, there is a glow discharge without light emission (transition phase, dark discharge), followed by an incandescent glow discharge with collisional electron avalanches (glow discharge and corona discharge: light is emitted by excited neutral atoms).
The preflash is a glow lamp, voltage decreases with increasing current, negative resistance with collisional electron conduction, an ion channel, not a ball filament. The process takes place at atmospheric pressure.
Then all charge carriers ionise by thermal emission, discharge into self-sustaining arc discharge. The contact with the ground is broken, the intensity of the flow increases.
Temperature is sufficient for thermal emission of electrons from gas molecules, inflating spherical shape above the ignition voltage, recombination of ions on the surface. This is the high temperature arc discharge stage, the warm plasma state, see video: https://www.youtube.com/watch?v=1bBNeyrMOJE.
The size of the sphere, and therefore the number of ions, is essentially constant, which is possible because the surface recombines as many ions as are produced inside it by thermal emission. Therefore, the pressure and temperature inside the sphere are approximately constant. Then, without any external energy source, it cools by consuming its own energy, the electromagnetic (light, heat) loss is strong, the particles recombine, the arc sphere collapses under the ignition voltage.
Upwards streamer emanating from the top of a pool cover (https://en.wikipedia.org/wiki/Lightning#cite_ref-57)
Assumed radial distributions: sphere size, volume, pressure are nearly constant, number of ions slowly decreases over time due to recombination. Temperature decreases both radially and over time due to heat loss. The surface may be characterised by electron luminosity (glow), due to the lower temperature and observations. Without an external energy source, it cools by consuming its own energy, has strong electromagnetic (light, heat) loss, and then collapses under the ignition voltage.
Above the ignition voltage, thermal ionisation inside the arc flash is typical. Recombination at the surface is typical, cooling, temperature distribution results in symmetrical spherical shapes. The radial density distribution of ions up to and near the half-arc can be maximum depending on the distance to which the as yet unionized oxygen and nitrogen molecules penetrate from the outside, from the surface.
Within the spherical filament, the free path lengths of electrons and positive ions are dominant, with electron path lengths of about 5.5 times. The collisions reduce the energy of the electrons and ions, and the energy loss from the collisions slows down the motion of the particles.
Above the ignition voltage, thermal ionisation inside the arc flash is typical. Recombination at the surface is typical, cooling, temperature distribution results in symmetrical spherical shapes. The radial density distribution of ions up to and near the half-arc can be maximum depending on the distance to which the as yet unionized oxygen and nitrogen molecules penetrate from the outside, from the surface.
Within the spherical filament, the free path lengths of electrons and positive ions are dominant, with electron path lengths of about 5.5 times. The collisions reduce the energy of the electrons and ions, and the energy loss from the collisions slows down the motion of the particles.
*Literature review: the ball lightning is not a rare phenomenon, many -though sometimes uncertain- observations have been published:
- History of observations Keul, A. G.: A brief history of ball lightning observations by scientists and trained professionals, Hist. Geo Space. Sci., 12, 43-56, https://doi.org/10.5194/hgss-12-43-2021, 2021.
- https://en.wikipedia.org/wiki/Ball_lightning,
- https://hu.wikipedia.org/wiki/G%C3%B6mbvill%C3%A1m,
- https://anyanyelvcsavar.blog.hu/2018/07/20/a_villamok_nepi_osztalyozasa_kulonos_tekintettel_
- https://anyanyelvcsavar.blog.hu/2018/07/20/a_villamok_nepi_osztalyozasa_kulonos_tekintettel_
a_gombvillamra,
- https://www.britannica.com/story/does-ball-lightning-exist.
- https://www.britannica.com/story/does-ball-lightning-exist.
- Corona discharge (https://en.wikipedia.org/wiki/Corona_discharge)
- Nicola Tesla may have produced ball lightning (https://en.wikipedia.org/wiki/Colorado_Springs_Notes,_1899%E2%80%931900) using high-voltage and high-frequency devices.
- At the Max Planc Institute (https://phys.org/news/2006-06-physicists-ball-lightning-lab.html), they produced plasma with a high current arc, but for a very short time compared to the lifetime of ball lightning.
- Researchers in Brazil and New Zealand have experimented with silicon evaporation (https://index.hu/tudomany/villam070112/, http://aparadox.hupont.hu/19/05-brazil-gombvillam). Microwave production experiments have also been carried out (https://www.nature.com/articles/srep28263).
- Nicola Tesla may have produced ball lightning (https://en.wikipedia.org/wiki/Colorado_Springs_Notes,_1899%E2%80%931900) using high-voltage and high-frequency devices.
- At the Max Planc Institute (https://phys.org/news/2006-06-physicists-ball-lightning-lab.html), they produced plasma with a high current arc, but for a very short time compared to the lifetime of ball lightning.
- Researchers in Brazil and New Zealand have experimented with silicon evaporation (https://index.hu/tudomany/villam070112/, http://aparadox.hupont.hu/19/05-brazil-gombvillam). Microwave production experiments have also been carried out (https://www.nature.com/articles/srep28263).
- Kapitza (Kapitza, P. L., Doklady, U.S.S.R. (1955) and https://www.nature.com/articles/185449a0) describes spherical lightning as electromagnetic standing waves, the resonance of a conducting ionized plasma sphere, which occurs when the wavelength of the radiation is about four times the diameter of the fireball. The ionic cohesive field: according to Kapitza (Kapitza, P. L., Doklady, U.S.S.R. (1955) and Silberg, P.A. On the formation of ball lightning. Il Nuovo Cimento C4, 221-235 (1981). https://doi.org/10.1007/BF02507400) the origin of the central cohesive field is an electromagnetic standing wave which on average produces a virtual potential minimum.
- Tibor Neugebauer (Fizikai Szemle, The theory of the fireball / NeugebauerTibor = Vol. 25, 1975, p. 49) describes a quantum theoretical idea based on the exchange interaction, which has not been generally accepted and is difficult to access even in Hungarian.
- There are also a number of ideas that cannot and should not be taken seriously.
- (https://web.archive.org/web/20050224120205/http://www.sulinet.hu/termeszetvilaga/archiv/2000/0015/21.html)
**Observed characteristics (https://en.wikipedia.org/wiki/Ball_lightning):
**Observed characteristics (https://en.wikipedia.org/wiki/Ball_lightning):
- https://www.youtube.com/watch?v=1bBNeyrMOJE,,
- Floating in an erratic orbit, ("mats"), spinning, rolls,
- destroys, though not always,
- often occurs in thunderstorms, but not exclusively and not necessarily thunderstorm related, although more common in thunderstorms,
- can move upwind, speeds of 1-2 m/sec,
- burning holes in partitions, sometimes passing through without a trace.
- Floating in an erratic orbit, ("mats"), spinning, rolls,
- destroys, though not always,
- often occurs in thunderstorms, but not exclusively and not necessarily thunderstorm related, although more common in thunderstorms,
- can move upwind, speeds of 1-2 m/sec,
- burning holes in partitions, sometimes passing through without a trace.
- spherical lightning bolts are described as transparent, opalescent with opaque edges, multicoloured, uniformly luminous, radiating flames, filaments or sparks, varying in shape from spheres, ovals, teardrops and rarely discs,
- disappear suddenly, dissipate gradually, or become engulfed in an object, "popping", exploding loudly, even forcefully, causing serious damage. Reports also vary on their alleged danger to humans, from lethal to harmless. Odours resembling ozone, burning sulphur or nitrogen oxides are often reported.
- They range from 1 to 100 cm in diameter, most often around 10 cm,
- A wide range of colours have been observed, the most common being red, orange and yellow, rarely bluish, usually opalescent.
- Their lifetime lasts from one second to more than a minute, and the brightness remains relatively constant during this time,
- observers rarely report any sensation of heat, but it will burn any object it comes into contact with. In some cases, the disappearance of the sphere has been accompanied by a strong release of heat.
- Some spheres are attracted to metal objects and move along conductors such as wires or metal fences.
- They range from 1 to 100 cm in diameter, most often around 10 cm,
- A wide range of colours have been observed, the most common being red, orange and yellow, rarely bluish, usually opalescent.
- Their lifetime lasts from one second to more than a minute, and the brightness remains relatively constant during this time,
- observers rarely report any sensation of heat, but it will burn any object it comes into contact with. In some cases, the disappearance of the sphere has been accompanied by a strong release of heat.
- Some spheres are attracted to metal objects and move along conductors such as wires or metal fences.
- Some have appeared inside buildings without warning, passing through locked doors and windows, and have also appeared inside metal aircraft, entering and leaving without causing damage.
- Possible spectra: silicon, calcium, iron, nitrogen, oxygen emission lines were observed in a Chinese spectral measurement from a long distance, probably partly pollution.