Plasma Volcanoes
Oct 28, 2009

"If I hadn't believed it, I never would have seen it with my own two eyes."
--- Dr. James C. Kroll

What we see is influenced by what we presume, so the skeptical scientist will make an effort to see things that aren’t readily explainable.

Common things to see around volcanoes are steam and ash plumes, pyroclastic flows, and lava rivers. Less common things are rotation of the plume, lightning around the column, and waterspouts or dust devils downwind under the plume. Since the invention of the seismograph, a sub-discipline of seismic study has developed.

The consensus explanations for volcanoes have lumbered into our modern world from the Age of Mechanics, when slide rules were state-of-the-art and things worked by bumping into each other. Convection is king: Hot, buoyant magma rises through cracks in rocks from the “magic mantle,” that mythical realm far below ground that generates excuses for mysterious phenomena on the ground.

When the magma ruptures the surface, steam and ash boil into the sky. Shear forces generate eddies, which become vertical and coalesce to impart rotation to the plume. Friction between ash particles generates static electricity, which discharges as lightning around the eruption column. Seismic signals are exclusively from displacements and mark out the extents of magma chambers beneath volcanoes.

The Age of Plasma, when computers are taken for granted and things work by electrical transmission, suggests more agile explanations. Discoveries from space and in plasma labs guide theories: A volcano could be the result of underground “lightning.” Peratt and Dessler favorably compared the “volcano” Prometheus on Jupiter’s moon Io to the plume of a plasma focus device. The contours of the plume indicated that the center of discharge was about two kilometers below the surface.

Because Io has no atmosphere, the plasma plume displays its pristine shape. On Earth, convection may alter the shape. Mechanical forces do have their places, although with the advent of plasma those places must be tested to separate reality from lumbering presumptions. Rotation may be driven by the circular forces in the Birkeland currents of the plume.

Consensus explanations have begun calling the copious lightning around many eruption columns “lightning sheaths.” Although they are not referring to the double-layer sheaths of plasma physics, the term may be appropriately carried over. The question of interest then becomes the inverse: Why do some ejection columns not exhibit a lightning sheath?

The occurrence of waterspouts and dust devils under plumes raises an interesting question for both consensus and plasma models. No one thought about electricity in respect to these phenomena until questions about the Martian dust devils led NASA researchers to measure electric fields near Arizona dust devils—and found strong ones. Although reflexively ascribed to triboelectricity (from friction), the plasma connection begs for further investigations.

Seismic signals are also an open question. If speaker wires from a hi-fi are inserted into a flame (for example, into the mantle of a Coleman lantern), the flame will “make music.” This is the principle behind once-popular plasma speakers. Because both magma and the crystals in rocks are forms of plasma, the explanation for seismic signals can no longer exclude the possibility that they are transduced between acoustic and electromagnetic modes.

Are ideas of Earth’s “liquid core” and “magic mantle” simply artifacts of outdated premises? Are the mechanical deep layers of the Earth instead electrical double layers that convert pressure and displacement waves into electrical waves and back again? Do the “quake signals” that supposedly delineate magma chambers actually indicate coronal discharges around an underground plasma focus?

Modern instruments are capable of testing explanations with greater rigor than is being done. The complacency of geologists is not due to a lack of technology but to a lack of scientific skepticism. Geologists’ unquestioned assumptions may well be hiding plasma volcanoes.

Mel Acheson