Kjell Prytz
Kjell Prytz | |
|---|---|
| Residence | Sweden |
| Nationality | Swedish |
| Known for | Field-free electrodynamics, Weber electrodynamics, the Prytz approximation |
| Scientific career | |
| Fields | Physicist |
| Institutions | Mälardalen University, Västerås (formerly University of Gävle) |
Kjell Prytz is a Swedish physicist at Mälardalen University in Västerås, and the author of Electrodynamics: The Field-Free Approach (Springer, 2015) — an undergraduate textbook that builds electromagnetism from the direct interaction of charges rather than from fields, and treats Weber's force law as a working tool rather than a historical curiosity.
He is an unusual figure in this catalogue in one respect: the heterodoxy is not at the margin of his career but inside a peer-reviewed Springer textbook series, and it sits alongside a substantial record in mainstream experimental particle physics.
Career and mainstream work
Prytz has been a senior lecturer and docent in physics since 1996, first at the University of Gävle — the affiliation recorded on this wiki — and latterly at Mälardalen University, where he works in the School of Education, Culture and Communication. He remains active, publishing in the American Journal of Physics as recently as 2026.
His earlier career was in high-energy physics, on the NMC muon experiment at CERN and on ZEUS at HERA, together with work on the ATLAS first-level calorimeter trigger. He is best known in that field for a single-author theoretical paper: "Approximate determination of the gluon density at low x from the F2 scaling violations" (Physics Letters B 311, 1993), which gives what is now generally called the Prytz approximation and has been cited on the order of a hundred times. He extended it to next-to-leading order the following year and returned to it in later papers.
He has since moved substantially into physics education research, and more recently into forestry and climate questions.
The field-free approach
Prytz's textbook inverts the usual order of presentation. Standard treatments introduce the electric and magnetic fields first and derive forces from them; Prytz bases the theory on force and mutual interaction between charges, and defers fields to the tenth of eleven chapters. The book — Electrodynamics: The Field-Free Approach: Electrostatics, Magnetism, Induction, Relativity and Field Theory — appeared in Springer's Undergraduate Lecture Notes in Physics series in 2015, running to 361 pages with full worked solutions, after a Swedish predecessor, Elektrodynamik i nytt ljus, in 2013.
The significance for this wiki is the framing. A direct-interaction formulation of electrodynamics is exactly the programme that Weber pursued in the nineteenth century and that was displaced by the Maxwell–Lorentz field picture; presenting it as the organising principle of an undergraduate course, in a mainstream series, is a considerably stronger claim than presenting it as history.
Weber electrodynamics
Prytz's specific contributions to the modern Weber literature are theoretical rather than experimental. Two stand out.
The first is a derivation of Weber's inductive, acceleration-dependent force from the detailed dynamics of two charges in parallel motion, and from that the Faraday–Henry law of induction — obtaining induction as a consequence of the pairwise force rather than as an independent field law.
The second is his "Meissner Effect in Classical Physics" (Progress In Electromagnetics Research M 64, 2018). The argument is that under Maxwell's electrodynamics a steady circulating current exerts no force on external charges at rest, whereas under Weber's law the charges carrying that current are centripetally accelerated, and the acceleration-dependent term does act on external charges at rest. The resulting induced current, he argues, accounts for the Meissner effect in classical terms. It is an analytic derivation rather than a measurement. Andre K T Assis and Martin Tajmar had reached the Meissner effect and the London moment from Weber's law by a different route the previous year.
He has also applied the approach to antenna theory, arguing that retarded time together with the Weber induction term reproduces loop-antenna behaviour.
Both contributions are cited by name in the standard modern review of the subject, Baumgärtel and Maher's "Foundations of Electromagnetism: A Review of Wilhelm Weber's Electrodynamic Force Law" (Foundations, 2022). The experimental side of the current Weber revival — unipolar induction and Ampère-bridge tests — is the work of the Liverpool group rather than Prytz, who is cited by them.
Relativity from the pairwise force
The paper catalogued on this wiki, Force Between Electric Charges: a New Approach to Relativity Theory, appeared in Galilean Electrodynamics (18, Special Issue 1, 2007), with a conference version given at the GIREP meeting in Ljubljana the previous year.
Its move is to run the usual derivation backwards. Rather than obtaining magnetism as a relativistic consequence of electrostatics — the standard textbook demonstration — Prytz starts from the pairwise electric and magnetic force between two charges, one at rest and one in uniform motion, and obtains time dilation from it. The derivation is, in his phrase, free from force fields and accordingly from the concept of light, which is the point: the relativistic result is made to follow from the interaction of charges rather than from a postulate about light propagation. A companion talk the same year addressed the equivalence of inertial and gravitational mass, and he returned to related ground in "Sources of inertia in an expanding universe" (Open Physics, 2015).
Reception
The particle-physics work is well cited; the electrodynamics is not. The Springer textbook has attracted on the order of a dozen citations and, so far as can be established, no published review in a physics journal. The Weber papers are cited within the small Weber-electrodynamics community — where Prytz is one of the named contributors — and essentially nowhere else; the current Wikipedia article on Weber electrodynamics does not mention him.
There is no record of his having presented at a Natural Philosophy Alliance or CNPS conference, and no evidence of collaboration with Andre K T Assis. His connection to this catalogue runs through the single Galilean Electrodynamics paper.
Papers on this wiki
- 2007 – Force Between Electric Charges: a New Approach to Relativity Theory — Galilean Electrodynamics 18, S1, 11–13.
Selected publications elsewhere
- "Approximate determination of the gluon density at low x from the F2 scaling violations", Physics Letters B 311, 286–290 (1993).
- Elektrodynamik i nytt ljus — Studentlitteratur, 2013.
- Electrodynamics: The Field-Free Approach — Springer, Undergraduate Lecture Notes in Physics, 2015. ISBN 978-3-319-13170-2.
- "Sources of inertia in an expanding universe", Open Physics 13 (2015).
- "Meissner Effect in Classical Physics", Progress In Electromagnetics Research M 64, 1–7 (2018).