Neuroradiological history: Sir Joseph Larmor and the basis of MRI physics

2000 ◽  
Vol 42 (11) ◽  
pp. 852-855 ◽  
Author(s):  
N. Tubridy ◽  
C. S. McKinstry
Keyword(s):  
Joseph Larmor

scholarly journals Sir Joseph Larmor, F. R. S

Nature ◽  
1942 ◽  
Vol 149 (3788) ◽  
pp. 631-633
Author(s):  
A. S. EDDINGTON
Keyword(s):  
Joseph Larmor

scholarly journals High Power THz Generation from Sub-ps Bunches of Relativistic Electrons

2004 ◽  
Vol 850 ◽  
Author(s):  
S. Benson ◽  
D. R. Douglas ◽  
H. F. Dylla ◽  
J. Gubeli ◽  
K. Jordan ◽  
...  
Keyword(s):  
High Power ◽  
Near Field ◽  
Fourth Power ◽  
Thz Spectroscopy ◽  
Relativistic Electrons ◽  
Time Resolved ◽  
Picosecond Pulses ◽  
Coulomb Term ◽  
Joseph Larmor ◽  
New Generation

ABSTRACTWe describe a > 100 Watt broadband THz source that takes advantage of the relativistic enhancement of the radiation from accelerating electrons according to the formula assigned the name of Sir Joseph Larmor[1, 2]. This is in contrast to the typical 1 milliwatt sources available in a laboratory. Specifically, for relativistic electrons the emission is enhanced by the fourth power of the increase in mass. Thus for 100 MeV electrons, for which the mass increases by a factor of ∼ 200, the enhancement is > 109. The experiments use a new generation of light source called an energy recovery linac (ERL) [3], in which bunches of electrons circulate once, but in which their energy is recovered. In such a machine the electron bunches can be very much shorter than those, say, in storage rings or synchrotrons.The Jefferson Lab facility operates in new limits of emission from relativistic particles involving both multiparticle coherence and near-field emission in which the velocity (Coulomb) term in the classical electrodynamical theory becomes as important as the acceleration term (synchrotron radiation).The sub-picosecond pulses of light offer unique capabilities in 2 specific areas, namely time-resolved dynamics, and imaging. High resolution THz spectroscopy has recently revealed sharp vibrational modes for many materials including malignant tissue, proteins, DNA, pharmaceuticals and explosive materials. Energetically the THz range embraces superconducting bandgaps, and regions of intense interest in the understanding of systems in which correlated motions of electrons are important, such as colossal magneto-resistive and high-Tc materials. The very high power levels of the new source will allow non-linear effects to be observed as well as the creation of novel states of materials, including electric-field driven localization[4]. We will give examples of existing work in these areas and present opportunities afforded by the new source.

Sir Joseph Larmor

1943 ◽  
Vol s1-18 (1) ◽  
pp. 57-64 ◽  
Author(s):  
E. Cunningham
Keyword(s):  
Joseph Larmor

scholarly journals The influence of the earth's magnetic field on electric transmission in the upper atmosphere

1928 ◽  
Vol 121 (787) ◽  
pp. 260-285 ◽  
Keyword(s):  
Magnetic Field ◽  
Upper Atmosphere ◽  
Displacement Current ◽  
Philosophical Magazine ◽  
Electric Transmission ◽  
Joseph Larmor ◽  
Velocity Of Propagation ◽  
The Waves ◽  
A Current ◽  
Exciting Wave

In the ‘Philosophical Magazine’ for December, 1924, Sir Joseph Larmor showed how wireless waves can be transmitted to great distances, round the protuberance of the curved earth, and without excessive damping, if the transmission takes place in an ionised region high in the ultra-rarefied upper atmosphere, in which the number of effective ions increases upwards. Under the influence of the waves the ions oscillate, and thus produce a current which must be added, in the electrodynamic equations of the exciting wave, to the aetherial displacement current. The velocity of propagation is thus altered to c ', where c ' -2 = c -2 (1-4 π N e 2 c 2 / mp 2 )

SIR JOSEPH LARMOR AND MODERN MATHEMATICAL PHYSICS

Science ◽  
1943 ◽  
Vol 97 (2508) ◽  
pp. 77-79
Author(s):  
G. D. BIRKHOFF
Keyword(s):  
Mathematical Physics ◽  
Joseph Larmor

Letters between Joseph Larmor and Vito Volterra

2002 ◽  
pp. 267-278
Author(s):  
Giorgio Israel ◽  
Ana Millán Gasca
Keyword(s):  
Joseph Larmor ◽  
Vito Volterra

On the critical equilibrium of the spiral spring pendulum

2009 ◽  
Vol 466 (2114) ◽  
pp. 407-421 ◽  
Author(s):  
P. Coullet ◽  
J.-M. Gilli ◽  
G. Rousseaux
Keyword(s):  
Nonlinear Oscillator ◽  
Inverted Pendulum ◽  
Physical Systems ◽  
Supercritical Bifurcation ◽  
Euler Elastica ◽  
Critical Equilibrium ◽  
Spiral Spring ◽  
Joseph Larmor ◽  
Angular Amplitude ◽  
First Time

Physical systems such as an inverted pendulum driven by a spiral spring, an unbalanced Euler elastica with a travelling mass, a heavy body with a parabolic section and an Ising ferromagnet are very different. However, they all behave in the same manner close to the critical regime for which nonlinearities are prominent. We demonstrate experimentally, for the first time, an old prediction by Joseph Larmor, which states that a nonlinear oscillator close to its supercritical bifurcation oscillates with a period inversely proportional to its angular amplitude. We perform our experiments with a Holweck–Lejay-like pendulum which was used to measure the gravity field during the twentieth century.

Frequency, theorem and formula: remembering Joseph Larmor in electromagnetic theory

1993 ◽  
Vol 47 (1) ◽  
pp. 49-60 ◽  
Keyword(s):  
World War I ◽  
Scientific Work ◽  
Electromagnetic Theory ◽  
Late Nineteenth Century ◽  
Lorentz Transformations ◽  
World War ◽  
Research School ◽  
Main Research ◽  
Joseph Larmor ◽  
Late Nineteenth

Joseph Larmor (1857-1942) was one of the most distinguished British mathematical physicists of the late-nineteenth century. He introduced both the electron and the so-called Lorentz transformations into physics. His book of 1900, Aether and Matter , l helped to establish a research school that guided the development of mathematical electromagnetic theory in Cambridge until the end of World War I. Today, however, Larmor is widely remembered by scientists for just two formulae and one theorem which, although correctly attributed to him, have been seen by historians of science as tangential to his main research interests. Indeed, none of the recent scholarly studies of Larmor’s scientific work even mention the now famous formulae and theorem. In this essay I review Larmor’s contribution to post-Maxwellian electromagnetic theory and explain the origin of the specific results upon which his reputation now rests.

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