Mystery of Lightning in the Iceland volcano solved by Nanoparticles?

Charge produced at the instant nanoparticles form upon rubbing of ash particle surfaces may solve the long-standing mystery of how lightning in volcanoes is electrified.

Background

The lightning observed in the plume of the Iceland volcano has renewed interest not only in how the volcano is electrified, but also how ice in the updraft of a thunderstorm produces lightning.

The electrification of volcanoes is generally thought caused by the rubbing of solid ash particles while that in thunderstorms is by the rubbing of ice particles. But the mechanism by which rubbing of particles produces the electrification has remained a mystery. See http://www.livescience.com/environment/volcano-lightning-Eyjafjallajokull-100420.html

Common belief is that rubbing removes electrons from particle surfaces, but this is unlikely because the electron is more tightly bound to the atom than the atoms are bound to each other, and therefore rubbing tends to only produce tiny clusters of neutral atoms called nanoparticles (NPs). Indeed, electrons are unlikely to be removed from a material by any form of mechanical energy. By the photoelectric effect, Einstein over a century ago showed only electromagnetic (EM) radiation may remove electrons from a material.

Hypothesis

Observation based on the foregoing allow the hypothesis that NPs comprising clusters of otherwise neutral atoms upon forming by rubbing solid surfaces somehow produce the EM radiation that by the photoelectric effect charges the NP by removing electrons.

Lightning by NPs in Thunderstorms

In the updraft of the thunderstorm, moisture is carried upward at high velocity and freezes at about 10,000 m. Submicron NPs may be formed directly from the moisture, but generally millimeter sized ice particles are produced. With the ice particles moving upward, other ice particles already having reached maximal height are falling downward to the earth under gravity. NPs generally form by the rubbing of particle surfaces in the collisions between upward and downward moving ice particles.

Of importance is the size differences between macroscopic particles and NPs. QM allows atoms in the macroscopic ice particles to have the thermal kT energy necessary absorb EM energy. Here QM stands for quantum mechanics, k for Boltzmann’s constant, and T for absolute. Classically, the atom in NPs is allowed to store the same amount of thermal energy as in macroscopic particles. But QM limits the amount of thermal energy stored by the atom depending on the particle size and temperature. At ambient and freezing temperatures, most of the thermal energy of the atom is stored at wavelengths greater than about 50 microns, but rapidly vanishes for NPs having wavelengths of a few microns. Therefore, at the instant the NPs form, the atoms have thermal energy in excess of that allowed by QM. If the NPs could increase in temperature, the excess thermal energy would be conserved. But QM also requires the specific heat of the atoms in NPs to vanish, and therefore the excess thermal energy cannot be conserved by an increase in temperature.

Conservation may only proceed by the QED induced up-conversion of the excess thermal energy in the FIR to the EM confinement frequency of the NP. Since the submicron size of the NP confines the FIR energy to EM frequencies in the UV and beyond, the NP spontaneously charge positive and emit electrons by the photoelectric effect. With the earth surface charged positive prior to the thunderstorm, the electrons attach to the downward falling ice particles and tend to charge the earth negative. Accumulation of charge from NPs during the storm therefore produces a large potential difference between the thundercloud and the earth that upon electrical breakdown creates cloud-to-ground lightning. However, the potential difference may occur within the thundercloud itself as commonly observed in cloud-to-cloud lightning.

However, only submicron NPs produce the ionizing radiation at UV or higher levels necessary to produce charge that electrifies the thunderstorm. Micron or larger sized ice articles that form on rubbing lack the EM confinement of thermal energy and only produce non-ionizing IR or FIR radiation.

Volcano Lightning by NPs

The charging process in volcanic lightning is similar to that in thunderstorms except that the NPs are produced by the rubbing of macroscopic particles of ash instead of ice. The ash particles are ejected from the volcano at high velocity only to collide and rub with those particles falling back to the volcano. Again, charge separation occurs as the positive charged NPs tend to move upward leaving the free electrons to attach to the downward falling particles.

Unlike thunderstorms, the ash need not move to high altitude to form solid particles, and therefore volcanic lightning is more efficient than that in thunderstorms, and therefore potential differences can reach breakdown over shorter separation distances. As shown in the thumbnail, volcano lightning is observed by electrical breakdown within the ash plume itself as in cloud-to-cloud lightning of thunderstorms.

Conclusions

The mysterious source of charge in thundercloud and volcano lightning finds commonality in the hypothesis that electrification in all natural processes is unified by rubbing NPs off solid surfaces. Other natural world mysteries possibly solved by NPs include Gecko walking on ceilings, X-rays from pulling Scotch tape from the roll, flow electrification in gasoline fires, ball lightning and St. Elmo’s fire, enhanced chemical reactions in tribochemistry. See “Unified Theory of Electrification in Natural Processes,” and other papers in http://www.nanoqed.org/ , 2009-10

Materials at the nanoscale have zero specific heat

Specific heat theories of Debye’s phonons and Einstein’s atomic vibrations including modification thereof by Raman are modified by quantum mechanics to include zero specific heat at the nanoscale.

Background

Specific heat is thought to be an intensive thermophysical property independent of the amount of the substance. Given the amount of the substance in a body is proportional to its volume, specific heat should therefore be independent of whether the body dimensions are macroscopic or nanoscopic. In contrast, specific heat that depends on the amount of the substance is an extensive property dependent on the dimensions of the body. See http://en.wikipedia.org/wiki/Specific_heat_capacity

Classical Specific Heat at the Nanoscale

Currently, specific heat at the nanoscale is considered an intensive property having the same value as for macroscopic bodies. The Debye and Einstein macroscopic theories of specific heat including modifications thereof by Raman are generally assumed in simulating heat transfer in nanostructures. See Thumbnail of “Macroscopic Specific Heat at the Nanoscale?”in http://www.prlog.org/10609553-materials-at-the-nanoscale-have-zero-specific-heat.html. What this means is the classical oscillators of statistical mechanics all having the same kT energy are used to model specific heat at the nanoscale.

Specific Heat by Quantum Mechanics

Contrarily, quantum mechanics (QM) embodied in the Einstein-Hopf relation for the harmonic oscillator shows the QM states do not have the same kT energy. At ambient temperature, the average Planck energy of QM states is kT only at thermal wavelengths greater than about 50 microns while at shorter wavelengths is less than kT and vanishes for nanostructures at submicron wavelengths. See Paper and Presentation at http://www.nanoqed.org at “Zero Specific Heat”, 2010.

Since the Planck energy at a given wavelength is the amount of thermal energy that can be stored in the QM oscillator, and since the only thermal wavelengths that can fit into nanostructures are submicron, QM requires zero specific heat capacity at the nanoscale, the consequence of which is absorbed heat cannot be conserved in nanostructures by an increase in temperature. Conservation may only proceed by the QED induced frequency up-conversion of absorbed heat to non-thermal EM radiation at the fundamental EM confinement frequency of the nanostructure, typically in the UV and beyond. The EM confinement is quasi-bound allowing leakage of QED induced radiation from the nanostructure to be absorbed in the macroscopic surroundings. See Ibid.

But QED emission in the UV and beyond from nanostructures is not readily observed – even by standard photomultipliers because of the UV cut-off, and therefore heat balances of nanostructures do not include QED emissions as heat losses. Hence, thermal conductivity is inferred to be reduced from that of the bulk to be consistent with the measured temperature difference across the body, e.g., as in thin films. If QED emissions are included in heat losses, the bulk conductivity need not be reduced for consistency with temperature differences thereby precluding any modification of Fourier’s theory of heat conduction by the Boltzmann transport equation (BTE). See Ibid.

Molecular Dynamics and Periodic Boundaries

Molecular Dynamics (MD) describes the classical solution of atomic motion based on Newton’s equations. To determine bulk transport properties, there are no QM restrictions on kT energy of atoms, i.e., atoms are assumed to have kT energy because the MD solution for the bulk is obtained by imposing periodic boundary conditions on the computational box. Historically, Monte Carlo (MC) preceded MD simulations, however. MC simulations of spherical particles in a submicron computational square with periodic boundaries were used to determine the 2D virial coefficients for the PVT equation of state. See Metropolis et al. Ibid. For a discrete nanostructure, periodic boundaries do not apply, and therefore the atoms in the nanostructure are subject to QM restrictions of zero kT energy.

Heat transfer of discrete nanostructures which are unambiguously not periodic is generally simulated by MD on the invalid assumption the atoms have kT energy. For nanocars, see e.g., http://pubs.acs.org/doi/full/10.1021/ct7002594 Extending specific heat from macroscopic samples to the nanoscale is just as invalid as extending the Dulong-Petit law for specific heat at ambient temperature to low temperatures about 200 years ago. Nevertheless, MD simulations of nanostructures today are proudly displayed in the belief they provide precise atomistic explanations of conduction heat transfer when in fact they are not valid because the simulations are performed on the assumption the atoms have finite kT energy. See http://www.scienceblog.com/cms/blog/8209-quantum-mechanics-questions-molecular-dynamics-submicron-structures-25639.html

Conclusions

1. QM requires zero specific heat capacity at the nanoscale be specified as a new thermophysical property of all materials.

2. The classification of specific heat as an intensive thermophysical property of a body should be changed to an extensive property depending on the dimensions of the body.

3. Nanoscale heat transfer based on the assumption of macroscopic specific heat is likely to produce unphysical results, e.g., reduced thermal conductivity in thin films.

4. There is no need for the BTE to determine the thermal conductivity in thin films as bulk conductivity may be assumed without any loss in accuracy.

5. Macroscopic Debye and Einstein theories should be revised to include zero specific heat at the nanoscale.

6. Lacking specific heat at the nanoscale, absorbed EM energy is not conserved by an increase in temperature, but rather by the emission of non-thermal QED induced EM radiation.

7. MD and MC simulations of bulk thermal conductivity based on full kT energy of atoms in submicron computational boxes under periodic boundary conditions are consistent with QM.

8. Zero specific heat is required for atoms in MD and MC simulations of discrete nanostructures without periodic constraints.

9. Absorbed EM energy in discrete nanostructures may be a priori assumed to be emitted as high frequency EM radiation that and absorbed in the macroscopic surroundings, thereby obviating any need to perform MD and MC simulations of the nanostructure itself.