# Lorentz force

In physics, the Lorentz force is the electromagnetic force exerted on a massive, charged particle in an electromagnetic field. It is named in honor of the Dutch physicist Hendrik Lorentz (1853–1928).

## Quotes

* The electrical conductivity of biological tissues can be measured through their sonication in a magnetic field: the vibration of the tissues inside the field induces an electrical current by Lorentz force. This current, detected by electrodes placed around the sample, is proportional to the ultrasonic pressure, to the strength of the magnetic field and to the electrical conductivity gradient along the acoustic axis. By focusing at different places inside the sample, a map of the electrical conductivity gradient can be established.
** P. Grasland-Mongrain, J.-M. Mari, J.-Y. Chapelon, and C. Lafon in (2013). "Lorentz force electrical impedance tomography". IRBM 34 (4-5): 357–360. ISSN 19590318. DOI:10.1016/j.irbm.2013.08.002.
* The interior of a neutron star is likely to be predominantly a mixture of superfluid neutrons and superconducting protons. This results in the quantization of the star’s magnetic field into an array of thin flux tubes, producing a macroscopic force very different from the Lorentz force of normal matter.
** S. K. Lander in (2013). "Magnetic Fields in Superconducting Neutron Stars". Physical Review Letters 110 (7). ISSN 0031-9007. DOI:10.1103/PhysRevLett.110.071101.
* ... the Lorentz force law does double service (1) as definer of fields and (2) as predicter of motions. Here and elsewhere in science, as stressed not least by Henri Poincaré, that view is out of date which used to say, "Define your terms before you proceed." All the laws and theories of physics, including the Lorentz force law, have this deep and subtle character, that they both define the concepts they use (here B and E ) and make statements about these concepts. Contrariwise, the absence of some body of theory, law, and principle deprives one of the means properly to define or even to use concepts. Any forward step in human knowledge is truly creative in this sense: that theory, concept, law, and method of measurement—forever inseparable—are born into the world in union.
** Charles W. Misner, Kip S. Thorne, and John Archibald Wheeler in Gravitation. Princeton University Press. 24 October 2017. p. 71. ISBN 978-0-691-17779-3.
* The ions of solutions exposed to the propagation of ultrasound in the presence of a magnetic field experience Lorentz force. Their movement gives rise to a local electric current density, which is proportional to the electric conductivity of the medium. In vitro assessment of this current is performed using simple models of biological media.
** A. Montalibet, J. Jossinet, A. Matias, and D. Cathignol in (2001). "Electric current generated by ultrasonically induced Lorentz force in biological media". Medical & Biological Engineering & Computing 39 (1): 15–20. ISSN 0140-0118. DOI:10.1007/BF02345261.
* Needle-free drug delivery by jet injection is achieved by ejecting a liquid drug through a narrow orifice at high pressure, thereby creating a fine high-speed fluid jet that can readily penetrate skin and tissue. Until very recently, all jet injectors utilized force- and pressure-generating principles that progress injection in an uncontrolled manner with limited ability to regulate delivery volume and injection depth. In order to address these shortcomings, we have developed a controllable jet injection device, based on a custom high-stroke linear Lorentz-force motor that is feed-back controlled during the time-course of an injection.
** Andrew Taberner, N. Catherine Hogan, and Ian W. Hunter in (2012). "Needle-free jet injection using real-time controlled linear Lorentz-force actuators". Medical Engineering & Physics 34 (9): 1228–1235. ISSN 13504533. DOI:10.1016/j.medengphy.2011.12.010.