Richard V. E. Lovelace

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Richard V. E. Lovelace
Richard V E Lovelace Kamch (cropped).jpg
Lovelace in 2004
Alma mater Washington University in St. Louis, Cornell University
Known forDiscovery of the period of the pulsar in the Crab Nebula (Crab pulsar)
ChildrenTwo
Scientific career
Institutions Cornell University
Thesis Theory and analysis of interplanetary scintillations

Richard Van Evera Lovelace is an American astrophysicist and plasma physicist. He is best known for the discovery of the period of the pulsar in the Crab Nebula (Crab pulsar), which helped to prove that pulsars are rotating neutron stars, for developing a magnetic model of astrophysical jets from galaxies, and for developing a model of Rossby waves in accretion disks. He organized a US-Russia collaboration in plasma astrophysics, which focused on modeling of plasma accretion and outflows from magnetized rotating stars.

Contents

Early life and education

Lovelace is the son of city planner Eldridge Lovelace and Marjorie Van Evera Lovelace. [1] [2] He graduated from Washington University in St. Louis in 1964 with a BS in physics and after receiving a National Science Foundation fellowship earned his PhD from Cornell University in 1970, also in physics, [3] with a dissertation titled Theory and analysis of interplanetary scintillations. [4]

Career

Lovelace began his career as a research associate at the U.S. Naval Research Laboratory and the Cornell University Laboratory of Plasma Studies. In 1972 he became an assistant professor at Cornell, and in 1984 a full professor. He spent a year as a visiting scientist at the Princeton University Plasma Physics Laboratory in the 1970s and in 1990 was a visiting professor at the University of Texas at Austin on a Guggenheim Fellowship. [5] He was elected an overseas fellow at Churchill College, Cambridge University, and visiting scientist at the Institute of Astronomy, Cambridge, and in 1999 was Orsan Anderson Visiting Scholar at Los Alamos National Laboratory. [6] He has a joint appointment at Cornell in the Astronomy and Applied Engineering Physics departments, and directed the Master of Engineering Program from 1991 to 2000.[ citation needed ] He was awarded the Excellence in Teaching Prize of the engineering honor society Tau Beta Pi in 1988.[ citation needed ]

He became a fellow of the American Physical Society in 2000, was divisional associate editor for Physical Review Letters for Plasma Physics from 1997 to 2000, in 2003 became associate editor of Physics of Plasmas, [6] and in 2010 became an editorial board member of Journal of Computational Astrophysics and Cosmology . [7] He was a member of the James Clerk Maxwell Prize for Plasma Physics committee of the American Physical Society in 2009-2011 and a member of the Advisory board of the Guggenheim Fellowship Foundation from 1994 to 2005. [3]

Research

In 1968, Lovelace and his collaborators discovered a rapidly pulsing radio source, the Crab Pulsar, measuring its period to be approximately 33 milliseconds. [8] As a graduate student working at Arecibo Observatory, Lovelace developed a version of the Fast Fourier transform program [9] which was adapted to run on the Arecibo Observatory's CDC 3200 computer. [10] This program helped to separate the periodic pulsar signal from the noise, and one night he discovered the period of the Crab pulsar. [11] A few weeks earlier, observers from the National Radio Astronomy Observatory reported about two pulsating sources near the Crab Nebula, with no evident periodicities. [12] [13] Lovelace and collaborators found that one of pulsars (the NP 0532) is located in the center of the Crab Nebula and found its period with a high precision: 33.09 ms. [11]

This was the fastest pulsar found at that time. [8] [14] This discovery helped to prove the idea that pulsars were rotating neutron stars. [15] [16] Before that, many scientists believed that pulsars were pulsating white dwarfs or neutron stars. [16] [17]

In 1976 Lovelace proposed a model of jets from magnetized disks surrounding massive black holes in galaxies. [18] [19] The model is based on the dynamo mechanism acting in the magnetized accretion disk surrounding a black hole or other gravitating object. The idea of the magnetically-driven jets and winds has been cited by the astronomical community. [20] [21] [22]

He also developed the theory of scintillations in the interstellar medium [23] and discovered the Kolmogorov nature of the turbulence in the solar wind. [24]

Lovelace proposed the Rossby wave instability in accretion disks [25] These waves form anti-cyclonic vortices in accretion discs, where dust particles accumulate and may form planets. [26] [27] He developed a theory of the stability of electron and ion rings which has been used in plasma fusion experiments at Cornell. [28]

Lovelace also has significant contributions to plasma physics. He developed the theory of the stability of electron and ion rings. [29] Lovelace developed a pioneering theory of intense ion beams in pulsed diodes, which are currently used in laboratories. [30] He also proposed the theory of magnetic insulation, which is used in laboratories. [31] Lovelace invented a trapping mechanism of spin-polarized neutral gas, which has been experimentally demonstrated. [32] [33]

Personal life

As of 2008 Lovelace was married; he has two daughters(Jennifer & Evera) . [1] He lives in Ithaca, New York. [34]

Related Research Articles

<span class="mw-page-title-main">Neutron star</span> Collapsed core of a massive star

A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects, neutron stars are the smallest and densest currently known class of stellar objects. Neutron stars have a radius on the order of 10 kilometres (6 mi) and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei.

<span class="mw-page-title-main">Crab Nebula</span> Supernova remnant in the constellation Taurus

The Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus. The common name comes from William Parsons, 3rd Earl of Rosse, who observed the object in 1842 using a 36-inch (91 cm) telescope and produced a drawing that looked somewhat like a crab. The nebula was discovered by English astronomer John Bevis in 1731, and it corresponds with a bright supernova recorded by Chinese astronomers in 1054. The nebula was the first astronomical object identified that corresponds with a historical supernova explosion.

In astroparticle physics, an ultra-high-energy cosmic ray (UHECR) is a cosmic ray with an energy greater than 1 EeV (1018 electronvolts, approximately 0.16 joules), far beyond both the rest mass and energies typical of other cosmic ray particles.

X-ray pulsars or accretion-powered pulsars are a class of astronomical objects that are X-ray sources displaying strict periodic variations in X-ray intensity. The X-ray periods range from as little as a fraction of a second to as much as several minutes.

<span class="mw-page-title-main">Pulsar wind nebula</span>

A pulsar wind nebula, sometimes called a plerion, is a type of nebula sometimes found inside the shell of a supernova remnant (SNR), powered by winds generated by a central pulsar. These nebulae were proposed as a class in 1976 as enhancements at radio wavelengths inside supernova remnants. They have since been found to be infrared, optical, millimetre, X-ray and gamma ray sources.

<span class="mw-page-title-main">Pulsar</span> Highly magnetized, rapidly rotating neutron star

A pulsar is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Earth, and is responsible for the pulsed appearance of emission. Neutron stars are very dense and have short, regular rotational periods. This produces a very precise interval between pulses that ranges from milliseconds to seconds for an individual pulsar. Pulsars are one of the candidates for the source of ultra-high-energy cosmic rays.

<span class="mw-page-title-main">Crab Pulsar</span> Pulsar in the constellation Taurus

The Crab Pulsar is a relatively young neutron star. The star is the central star in the Crab Nebula, a remnant of the supernova SN 1054, which was widely observed on Earth in the year 1054. Discovered in 1968, the pulsar was the first to be connected with a supernova remnant.

<span class="mw-page-title-main">Astrophysical jet</span> Beam of ionized matter flowing along the axis of a rotating astronomical object

An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as an extended beam along the axis of rotation. When this greatly accelerated matter in the beam approaches the speed of light, astrophysical jets become relativistic jets as they show effects from special relativity.

<span class="mw-page-title-main">Millisecond pulsar</span> Pulsar with a rotational period less than about 10 milliseconds

A millisecond pulsar (MSP) is a pulsar with a rotational period less than about 10 milliseconds. Millisecond pulsars have been detected in radio, X-ray, and gamma ray portions of the electromagnetic spectrum. The leading theory for the origin of millisecond pulsars is that they are old, rapidly rotating neutron stars that have been spun up or "recycled" through accretion of matter from a companion star in a close binary system. For this reason, millisecond pulsars are sometimes called recycled pulsars.

Neutron star spin up is the name given to the increase in rotational speed over time first noted in Cen X-3 and Her X-1 but now observed in other X-ray pulsars. In the case of Cen X-3, the pulse period is decreasing over a timescale of 3400 years.

<span class="mw-page-title-main">Outline of astronomy</span>

The following outline is provided as an overview of and topical guide to astronomy:

<span class="mw-page-title-main">Homopolar generator</span> Type of direct current electrical generator

A homopolar generator is a DC electrical generator comprising an electrically conductive disc or cylinder rotating in a plane perpendicular to a uniform static magnetic field. A potential difference is created between the center of the disc and the rim with an electrical polarity that depends on the direction of rotation and the orientation of the field. It is also known as a unipolar generator, acyclic generator, disk dynamo, or Faraday disc. The voltage is typically low, on the order of a few volts in the case of small demonstration models, but large research generators can produce hundreds of volts, and some systems have multiple generators in series to produce an even larger voltage. They are unusual in that they can source tremendous electric current, some more than a million amperes, because the homopolar generator can be made to have very low internal resistance. Also, the homopolar generator is unique in that no other rotary electric machine can produce DC without using rectifiers or commutators.

In X-ray astronomy, quasi-periodic oscillation (QPO) is the manner in which the X-ray light from an astronomical object flickers about certain frequencies. In these situations, the X-rays are emitted near the inner edge of an accretion disk in which gas swirls onto a compact object such as a white dwarf, neutron star, or black hole.

<span class="mw-page-title-main">Stellar magnetic field</span> Magnetic field generated by the convective motion of conductive plasma inside a star

A stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star. This motion is created through convection, which is a form of energy transport involving the physical movement of material. A localized magnetic field exerts a force on the plasma, effectively increasing the pressure without a comparable gain in density. As a result, the magnetized region rises relative to the remainder of the plasma, until it reaches the star's photosphere. This creates starspots on the surface, and the related phenomenon of coronal loops.

<span class="mw-page-title-main">PSR B1937+21</span> Pulsar in the constellation Vulpecula

PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21. The name PSR B1937+21 is derived from the word "pulsar" and the declination and right ascension at which it is located, with the "B" indicating that the coordinates are for the 1950.0 epoch. PSR B1937+21 was discovered in 1982 by Don Backer, Shri Kulkarni, Carl Heiles, Michael Davis, and Miller Goss.

PSR J1614–2230 is a pulsar in a binary system with a white dwarf in the constellation Scorpius. It was discovered in 2006 with the Parkes telescope in a survey of unidentified gamma ray sources in the Energetic Gamma Ray Experiment Telescope catalog. PSR J1614–2230 is a millisecond pulsar, a type of neutron star, that spins on its axis roughly 317 times per second, corresponding to a period of 3.15 milliseconds. Like all pulsars, it emits radiation in a beam, similar to a lighthouse. Emission from PSR J1614–2230 is observed as pulses at the spin period of PSR J1614–2230. The pulsed nature of its emission allows for the arrival of individual pulses to be timed. By measuring the arrival time of pulses, astronomers observed the delay of pulse arrivals from PSR J1614–2230 when it was passing behind its companion from the vantage point of Earth. By measuring this delay, known as the Shapiro delay, astronomers determined the mass of PSR J1614–2230 and its companion. The team performing the observations found that the mass of PSR J1614–2230 is 1.97 ± 0.04 M☉. This mass made PSR J1614–2230 the most massive known neutron star at the time of discovery, and rules out many neutron star equations of state that include exotic matter such as hyperons and kaon condensates.

<span class="mw-page-title-main">Franco Pacini</span> Italian astrophysicist

Franco Pacini was an Italian astrophysicist and professor at the University of Florence. He carried out research, mostly in High Energy Astrophysics, in Italy, France, United States and at the European Southern Observatory.

<span class="mw-page-title-main">PSR J0348+0432</span> Pulsar–white dwarf binary system in Taurus constellation

PSR J0348+0432 is a pulsar–white dwarf binary system in the constellation Taurus. It was discovered in 2007 with the National Radio Astronomy Observatory's Robert C. Byrd Green Bank Telescope in a drift-scan survey.

<span class="mw-page-title-main">Rossby wave instability in astrophysical discs</span> Rossby

Rossby Wave Instability (RWI) is a concept related to astrophysical accretion discs. In non-self-gravitating discs, for example around newly forming stars, the instability can be triggered by an axisymmetric bump, at some radius , in the disc surface mass-density. It gives rise to exponentially growing non-axisymmetric perturbation in the vicinity of consisting of anticyclonic vortices. These vortices are regions of high pressure and consequently act to trap dust particles which in turn can facilitate planetesimal growth in proto-planetary discs. The Rossby vortices in the discs around stars and black holes may cause the observed quasi-periodic modulations of the disc's thermal emission.

<span class="mw-page-title-main">Accretion disk</span> Structure formed by diffuse material in orbital motion around a massive central body

An accretion disk is a structure formed by diffuse material in orbital motion around a massive central body. The central body is typically a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward towards the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object's mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology.

References

  1. 1 2 Eldridge Lovelace obituary, Kansas City Star, November 27, 2008.
  2. ↑ "Dr. Virginia Utermohlen Married", New York Times, December 23, 1972.
  3. 1 2 "Richard V E Lovelace", College of Engineering, Cornell University, retrieved January 2, 2021.
  4. ↑ Richard Van Evera Lovelace, "Theory and analysis of interplanetary scintillations", PhD, Cornell University, 1970, OCLC   1055559284.
  5. ↑ "John Simon Guggenheim Foundation | Richard V. E. Lovelace" . Retrieved 2021-01-07.
  6. 1 2 "Richard V.E. Lovelace", Department of Astronomy, College of Arts and Sciences, Cornell University, retrieved January 2, 2021.
  7. ↑ Editorial Board of the "Journal of Computational Astrophysics and Cosmology"
  8. 1 2 "Out of the zenith. Jodrell Bank 1957-1970" Sir. Bernard Lovell 1973, London: Oxford University Press, pp 1-255 (see page159).
  9. ↑ "Gauss and the history of the fast Fourier transform" Heideman, Michael T., Johnson, Don H., Burrus, Charles Sidney 1984. (PDF). IEEE ASSP Magazine. 1 (4): 14–21.
  10. ↑ "On the Discovery of the Period of the Crab Nebula Pulsar" Cornell University
  11. 1 2 "Astrophysical formulae. space, time, matter and cosmology" Kenneth R. Lang 2014, Publisher: Springer Berlin Heidelberg
  12. ↑ "Pulsating radio sources near Crab Nebula" Howard, W. E., Staelin, D. H., Reifenstein, E. C. 1968, IAU Circ., No. 2110, #2
  13. ↑ "Pulsating radio sources near the crab nebula" Staelin, David H. and Reifenstein, Edward C., III, December 1968, Science, Volume 162, Issue 3861, pp. 1481-1483
  14. ↑ Haensel, Paweł. (2007). Neutron stars. 1, Equation of state and structure. Potekhin, A. Y., Yakovlev, D. G. New York: Springer. ISBN   978-0-387-47301-7. OCLC   232363234.
  15. ↑ "Rotating neutron stars as the origin of the pulsating radio sources" T. Gold 1968, Nature, Volume 218, Issue 5143, pp. 731-732
  16. 1 2 "Recent observations of pulsars support the rotating neutron star hypothesis." T. Gold, 1969, Nature, Volume 221, Issue 5175, pp. 25-27.
  17. ↑ “Observations of a rapidly pulsating radio source” A. Hewish, S. J. Bell, J. D. H. Pilkington, P. F. Scott and R. A. Collins 1968, Nature, 217, 709-713.
  18. ↑ "Dynamo model of double radio sources" R. V. E. Lovelace 1976, Nature 262 (5570), 649-652.
  19. ↑ “Accretion disc electrodynamics - a model for double radio sources” Blandford, R. 1976, MNRAS, 176, 465-481 (see p. 465)
  20. ↑ ``Hydromagnetic flows from accretion discs and the production of radio jets R. D. Blandford, and D. G. Payne 1982, MNRAS, 199, 883-903 (see p. 884)
  21. ↑ ``Self-similar models of magnetized accretion disks A. Konigl 1989, Astrophysical Journal, 342, 208-223 (see p. 208)
  22. ↑ “Black holes, white dwarfs, and neutron stars: the physics of compact objects” S. L. Shapiro and S. A. Teukolsky 1983, A Wiley-Interscience Publication, New York: Wiley, pp 1-645 (see p. 437)
  23. ↑ "Refractive and diffractive scattering in the interstellar medium" J. M. Cordes, A Pidwerbetsky, R. V. E. Lovelace The Astrophysical Journal 310, 737-767
  24. ↑ "Analysis of observations of interplanetary scintillations" R. V. E. Lovelace, E. E. Salpeter, L. E. Sharp, & D. E. Harries 1970, ApJ, 159, p. 1047.
  25. ↑ "Rossby wave instability of Keplerian accretion disks" R. V. E. Lovelace, H. Li, S. A. Colgate, A. F. Nelson 1999, The Astrophysical Journal 513 (2), 805.
  26. ↑ A Major Asymmetric Dust Trap in a Transition Disk N. van der Marel, E. F. van Dishoeck, S. Bruderer, etc. 2013, Science Vol. 340, Issue 6137, pp. 1199-1202
  27. ↑ Astrophysics of planet formation P. J. Armitage, Cambridge University Press
  28. ↑ "Intense pulsed ion beams for fusion applications" S. Humphries Jr. 1980, Nuclear Fusion 20, 1549-1612, see pp. 1560, 1572, 1589
  29. ↑ "Low-frequency stability of Astron configurations" R. V. E. Lovelace 1975, Physical Review Letters 35 (3), 162-164.
  30. ↑ "Generation of intense ion beams in pulsed diodes". R. N. Sudan and R. V. Lovelace 1973, Physical Review Letters 31 (19), 1174.
  31. ↑ "Theory of magnetic insulation" R. V. Lovelace, E. Ott 1974, The Physics of Fluids 17 (6), 1263-1268.
  32. ↑ "Magnetic confinement of a neutral gas" R. V. E. Lovelace, C. Mehanian, T. J. Tommila, D. M. Lee 1985, Nature 318 (6041), 30-36.
  33. ↑ "Storage rings for spin polarized hydrogen" D. Thompson, R. V. E. Lovelace, D. M. Lee 1989, Journal of the Optical Society of America, 611.
  34. ↑ "Marjorie Remembers" (PDF). 2016-03-03. Archived (PDF) from the original on 2016-03-03. Retrieved 2021-01-19.
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