| 06 Aug 2025
A magnetogenic framework integrating planetary magnetism and heat
Abstract. Planetary magnetic fields are commonly thought to be generated by a planet-interior dynamo, wherein convection cells convert mechanical to magnetic energy via induced electric currents. Europa and Callisto’s fields however are spawned by currents that are induced by the magnetic flux generated during their passage through Jupiter’s field, and are therefore generated via a magnetic to electric to magnetic energy conversion. The Earth-incident solar wind deformation of the geomagnetic field induces similar currents in Earth’s Outer Core. This article documents how solar wind induced currents regenerate the geomagnetic field and how waste heat from their magnetogenesis causes regional geothermal anomalies. This newly developed Solar Wind Induced Electric Dynamo (SWIED) framework explains the presence, magnitude, geometry and stability of the Earth’s dipolar and non-dipolar fields, as well as its current polarity. It clarifies the origins of Earth’s fluid Outer and solid Inner Core, and offers realistic mechanisms for geomagnetic excursions and reversals, secular non-dipole drift, and solar signals in the geomagnetic power spectrum. It accounts for the areas of high surface heat flow that originate in the Outer Core, thereby establishing the link between magnetogenesis, volcanism and continental drift.
The Gas and Ice Giants’ magnetic fields are very likely generated by similar SWIEDs, whose by-product is substantial magnetogenic waste heat that significantly contributes to emitted planetary radiation, largely explaining why these planets emit more energy than they receive through solar irradiation alone. The SWIED model rationalizes their magnetic field geometries and heat anomalies, and accurately hindcasts their magnetic field strengths from best-estimate input data.
This manuscript claims to propose a new framework for explaining the origin of the Earth’s magnetic field and its temporal variability on millennial (dipole reversals and excursions), centennial (secular variation), and shorter timescales. The proposed framework is based on the assumption that solar-wind- and magnetospherically induced electric currents regenerate and sustain the internal geomagnetic field. This central assumption is in direct contradiction with well-established geodynamo theory and with basic observational constraints.
The proposed framework is introduced and discussed primarily in Sect. 4, where the author argues that externally driven currents associated with the solar wind and magnetosphere can regenerate the internal geomagnetic field. This interpretation is physically incorrect and renders the subsequent discussion untenable. It is well established that magnetic fields generated by external sources cannot penetrate to the Earth’s outer core, where dynamo action operates. This is due to the fact that the mantle is a poor electric conductor and effectively shields the core from rapid electromagnetic induction, preventing externally generated fields from influencing the geodynamo.
The manuscript further claims that Joule heating associated with solar-wind-induced currents can produce significant regional thermal anomalies in the outermost parts of the core. Even if weak secondary currents of external origin were to penetrate the core, the associated Ohmic dissipation would be negligibly small and incapable of affecting the geodynamo.
It is also well established that variations of the geomagnetic dipole observed at the Earth’s surface on timescales of hundreds of years or longer (secular variation, polarity reversals and excursions) arise from internal core dynamics, contrary to what is claimed in the manuscript. In fact, magnetic field variations of external origin are of small amplitude. At the Earth’s surface, the magnetic field generated by external sources typically has amplitudes of only a few nT, whereas the internally generated (dynamo) field has a mean intensity of roughly 40,000 nT.
All these points are standard results in geomagnetism and can be found in any geophysics textbook (e.g. Merrill et al., “The magnetic field of the Earth”, 1996; Lowrie, “Fundamentals of Geophysics”, 2007). As a consequence, the manuscript’s central claim – that solar-wind-induced currents can regenerate and sustain the internal geomagnetic field – is not physically viable. This fundamental issue undermines the proposed framework and the conclusions drawn from it.