Balthasar van der Pol

Balthasar van der Pol (1889–1959) was a Dutch physicist known for the van der Pol oscillator.

Biography Balthasar van der Pol was born on 27 January 1889 in Utrecht, Netherlands, the son of Balthazar van der Pol and Gerhardina Clasina Steffens. From 1911 to 1916, he studied physics at Utrecht University. After graduation, he travelled to England, where he worked under Ambrose Fleming at University College London and J. J. Thomson at the University of Cambridge. While in England, he studied the heuristics of wireless reception onboard ships.

On 2 June 1917 in London, Van der Pol married Pietronetta Posthuma, with whom he had a son and two daughters.

In 1919, upon his return to the Netherlands, Van der Pol became an assistant to Hendrik Lorentz at Teylers Museum in Harlem and returned to Utrecht University. The following year, he received his Ph.D. under Willem Henri Julius at Utrecht.

“[Van der Pol] tried to find differential equations which illustrated general problems but which were simple enough to investigate mathematically. When mathematics would carry him no further, he set up circuits satisfying the differential equations and investigated the system empirically."

The differential equations of coupled electrical systems drew his interest, and he developed the idea of "relaxation oscillations". With J. van der Mark he applied the idea to the heartbeat, which provided one of the earliest quantitative models of the action potential. These studies led him to the van der Pol equation and Oliver Heaviside’s operational calculus for dealing with differential equations. He submitted articles to Philosophical Magazine on the operational calculus and, in coordination with H. Bremmer, wrote Modern Operational Calculus based on the Two-sided Laplace Integral, published by Cambridge University Press.

Awards and honours In 1935, Van der Pol was awarded the Medal of Honor by the Institute of Radio Engineers "for his fundamental studies and contributions in the field of circuit theory and electromagnetic wave propagation phenomena".

The asteroid 10443 van der Pol is named after him.

In 1949, Van der Pol became a Member of the Royal Netherlands Academy of Arts and Sciences.

Works 1928: (with J van der Mark) The Heartbeat considered as a Relaxation oscillation, and an Electrical Model of the Heart. Phil. Mag. Suppl. No. 6 pp 763–775 1947: An electro-mechanical investigation of the Riemann zeta function in the critical strip, Bulletin of the American Mathematical Society 53: 976–81 1964: (with H. Bremmer) Operational Calculus Cambridge University Press 1960: Selected Scientific Papers, North-Holland Two volumes