title: Low- and high-frequency nonlinear acoustic phenomena in a magnesite.
abstract: The results of experimental and theoretical studies of nonlinear acoustic phenomena (amplitude-dependent losses, resonant frequency shifts, damping of weak ultrasonic pulses and their carrier frequency phase delay under action of a powerful low-frequency pumping wave as well as amplitude-phase self-action of the finite-amplitude ultrasonic pulses) in a magnesite rod are presented. Analytical description of the observed phenomena was carried out within the frameworks of the phenomenological state equations that contain low-frequency hysteretic nonlinearity and both high-frequency dissipative and elastic nonlinearity. From comparison of experimental and analytical amplitude-frequency dependences of nonlinear phenomena, the values of magnesite acoustic nonlinearity parameters were determined. The frequency dependences have been discovered for hysteretic (in a range 3.6-17.2 kHz) as well as dissipative and elastic nonlinearity (in a range 50-370 kHz).
authors.affiliation: Institute of Applied Physics RAS, 46 Uljanov Str., Nizhny Novgorod 603950, Russia. Electronic address: nazarov@hydro.appl.sci-nnov.ru.
authors.forename: V E
authors.initials: VE
authors.lastname: Nazarov
authors.forename: A B
authors.initials: AB
authors.lastname: Kolpakov
mesh_terms: D003198:Computer Simulation; D004735:Energy Transfer; D019220:High-Energy Shock Waves; D008274:Magnesium / Q000737:chemistry* / Q000528:radiation effects*; D008422:Materials Testing; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D011829:Radiation Dosage; D012542:Scattering, Radiation; D013016:Sound
chemical_list: C005479:magnesium carbonate; D008274:Magnesium
keywords: Dissipative and elastic nonlinearity; Hysteresis; Nonlinear acoustic waves; Ultrasonic pulses