This article has had nearly citations. He was an active artist and, within his local Arts club, arranged exhibitions which always included examples of his own work. At least four of his truly seminal ideas, still widely used and including the description of the Hillas parameters, were published only in conference proceedings. His scientific passion was cosmic-ray physics and his unique skills were a major factor in the very high international standing in which the Department was once held in this field. He collected rocks, pebbles and fossils and avidly followed radio and TV programs dealing with geology. Wilson did eventually get Michael involved in the interpretation of data from the Haverah Park project though Michael kept well away from the operation of the instrument itself. Finally, with all planets included, his results replicated both the period and magnitude claimed by Milankovitch — interestingly Saturn now made a difference, not directly, but through its influence on Jupiter. He was awarded the Rutherford Medal of the Institute of Physics in
AIP Publishing p He involved himself very little in committee work within the University or nationally or internationally. Particles in that charge distribution co-rotate with the star until the distance where the linear velocity reaches the speed of light. This allows us to estimate the charge density in the magnetosphere, i. This description is supported by the observational growth of fast, massive and highly magnetized WDs [ 6 , 18 , 19 , 20 ]. Tributes to him have poured in from all continents including Antarctica. Michael had outstanding talents both as an experimental physicist and as a numerical modeller of physical phenomena.
AIP Publishing p Emeritus Professor Michael Hillas Colleagues will be sorry to learn of the death, on 26 Novemberof Emeritus Professor Michael Hillas, at the age of 85 after a short period of ill-health.
He was a keen hill walker and, while delighting in the scenery for its own sake, he always sought to ;lot the geological background. This is a general geometrical criterion known as the Hillas criterion for all types of cosmic ray sources [ 30 ].
So clarity was achieved even if the resulting change in solar radiation was much too small to be the sole driving force.
Ultra-high energy cosmic rays from white dwarf pulsars and the Hillas criterion Ronaldo V. The following obituary has been prepared cosjic colleagues and friends.
The work for which Michael will perhaps be best remembered started in the late s when he pointed out that techniques could be developed to separate gamma-rays from hadrons in the cosmic rays at an energy of around eV using large mirrors to detect the Cherenkov light which these low-energy cosmic-rays produce in the atmosphere.
The funeral service will be held at More recently Kashiyama et al. This rapidly rotating magnetized WD would simulate the neutron star pulsars as pointed out by Geng et al. Indeed, his record on any computing device showed him to be vastly superior to any one else in his ability to attain results of importance with high efficiency — and he always had a good idea of the answer before he ran the program.
Scientists from Durham, Leicester, Liverpool and Oxford Universities are involved, though regrettably there are none from Leeds University where the fundamental ideas for the instrument were born. All agree that he had a brilliant mind. As an undergraduate, he had taken Geology as a subsidiary subject Continental Drift was then treated with considerable scepticism and it remained an absorbing interest throughout his life and especially so after his retirement.
This description is supported by the observational growth of fast, massive and highly magnetized WDs [ 6181920 ]. There is a gap h above the polar region, and the potential difference becomes [ 33 ]. After his retirement, Michael remained in the Department of Physics and Astronomy as a Research Professor working on TeV gamma-ray astronomy, the field that he had done so much to create. His scientific passion was cosmic-ray physics and his unique skills were a major factor in the very high international standing in which the Department was once held in this field.
Michael also contributed enormous insights to the problem of the acceleration of cosmic rays.
The outside world knew and revered Michael for his research many international “names” came to Leeds to a symposium held in his honour in April When he got his chair inhe had published fewer than 30 papers in refereed journals. His eccentricities only added to his charm. His final Monte Carlo program for high-energy shower studies, known as MOCCA, was used extensively in the design of what became the Pierre Auger Observatory, the largest cosmic ray detector ever built and which now covers a land area of the size of West Yorkshire in Western Argentina.
Secretariat Home Contact us You are here: He had been scarred while running the cosmic-ray detectors at Harwell where he had to rayd cables in the field at night after rabbits had eaten through them. Similarly, the sources above the blue and orange lines are able to accelerate protons up cosmix 10 20 eV and 10 21 eV, respectively.
Ihllas did physics ploh he loved his subject and was always extremely modest about his achievements. Neglecting energy losses, i.
Gaisser–Hillas function – Wikipedia
rags At a young age he could add and subtract logarithms in his head while hillxs the days before computers or electronic calculators were available, his prowess on the slide rule was legendary. Particles accelerated in comic sources could be a fraction of ultra-high cosmic ray hillae in our planet. His conclusions were never published. While at Harwell inalong with Cranshaw, he measured the absolute difference between the charges of the proton and the electron, showing it to be less than times the electronic charge: With a combination of insight and calculation, he developed new ways of looking at the showers initiated by the high-energy cosmic rays, thus playing a pivotal role in maximising the interpretation of the information which came from the cosmic-ray experiment at Haverah Park, helping to bring that work to international prominence.
As discussed in [ 13 ]the process of release energy for dipole radiation in a white dwarf can be explained in terms of a canonical spin-powered pulsars model, since in certain aspects they are similar see e.
Particles in that charge distribution co-rotate with the star until the distance where the linear velocity reaches the speed of light. He was promoted to a Readership in and to a Personal Chair in Physics in Michael was a quiet and modest man, hillaas but with great personal charm.
Following the last consideration there are new values for the mass density, moment of inertia, dipole moment and rotation energy [ 1617 ].