The Center for Theoretical Geo/Cosmo Plasma Physics was established by the Air Force Office of Scientific Research in 1986 through a DoD University Research initiative (URI) Grant via keen national competition. The goal of the center since its inception has been to develop and maintain a program of excellence in interdisciplinary space plasma research involving the mutual interactions of collaborating members of a select group of space scientists, plasma physicists, mathematicians and numerical...
Topics: DTIC Archive, Chang, Tom T, MASSACHUSETTS INST OF TECH CAMBRIDGE, *PLASMASPHERE, AIR FORCE...
We have achieved all the goals stated in our grant proposal in collaboration with Dr. C.C. Wu of the University of California at Los Angeles. Specifically, these include: The understanding of the complexity induced nonlinear spatiotemporal structures and the coexisting propagating modes. The development of plasma resonances and coherent structures in space plasmas. The study of fluctuation-induced nonlinear instabilities and their role in the reconfiguration of magnetic topologies in the...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD CONFIGURATIONS, NONLINEARITY, PLASMA...
Results of a seven-year study of a variety of multiscale plasma processes in the ionosphere and magnetosphere are described. Specific topics discussed in detail include: (1) ion energization and outflow; (2) self-organized criticality and multiscale intermittent turbulence in the plasma sheet; and (3) a new theory of the nonclassical polar wind. A complete listing of published papers and books during the years 1992-1998 is also included.
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
We have achieved all the goals stated in our grant proposal. Specifically, these include: 1. The understanding of the complexity induced nonlinear spatiotemporal coherent structures and the coexisting propagating modes. 2. The understanding of the intermittent turbulence and energization process of the observed Bursty Bulk Flows (BBF's) in the Earth s magnetotail. 3. The development of "anisotropic three-dimensional complexity" in the plasma sheet due to localized merging and...
Topics: NASA Technical Reports Server (NTRS), SPACE PLASMAS, NONLINEARITY, MAGNETIC FIELD CONFIGURATIONS,...
The major accomplishment of the research was the comparision of the effects of wave-particle interactions and the kinetic suprathermal electron population on the acceleration of the solar wind.
Topics: NASA Technical Reports Server (NTRS), SOLAR WIND, WAVE-PARTICLE INTERACTIONS, PARTICLE...
The Center for Theoretical Geoplasma Physics was established at MIT through an AFOSR University Research Initiative grant. The goal of the Center since its inception has been to develop and maintain a program of excellence in interdisciplinary geoplasma research involving the mutual interaction of ionospheric scientists, aeronomists, plasma physicists and numerical analysts. During the past three years under the current research Grant 'Frontier Geoplasma Research', members of the center have...
Topics: DTIC Archive, Chang, Tom T., MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
In 1981, Chang and Coppi (Geophys. Res. Lett., 8, 1253) suggested that lower hybrid turbulence could be the prime candidate for the acceleration of ions and generation of ion conics in the high latitude ionosphere and magnetosphere. Subsequently, Retterer, Chang and Jasperse (J Geophys. Res., 91, 1609 (1986)) demonstrated that nonlinear wave interactions near the lower hybrid frequency through modulational instability, such as the collapse of waves into soliton (caviton) turbulence could play a...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
We are concerned with the plasma wave radiations and turbulence, generated by natural or artificially produced charged beams and currents or plasma anisotropy, in the Earth's ionosphere and magnetosphere--particularly in the topside ionosphere and the suprauroral region. Specific problems studied during the three-year contract period include: ion conics and beams, lower hybrid waves and hybrid whistlers, nonlinear electrostatic ion cyclotron waves and cavitations, the beam-plasma-discharge...
Topics: DTIC Archive, Chang,Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
The Center for Theoretical Geo/Cosmo Plasma Physics was established by the Air Force Office of Scientific Research in 1986 through a DoD University Research Initiative (URI) Grant via keen national competition. The goal of the center since its inception has been to develop and maintain a program of excellence in interdisciplinary space plasma research involving the mutual interactions of collaborating members of a select group of space scientists, plasma physicists, mathematicians and numerical...
Topics: DTIC Archive, Chang, Tom T, *PLASMASPHERE, COUPLING(INTERACTION), IONOSPHERE, POLAR REGIONS, AIR...
The Center for Theoretical Geoplasma Physics was established at MIT in 1986 through an AFOSR University Research Initiative grant. The goal of the Center since its inception has been to develop and maintain a program of excellence in interdisciplinary geoplasma research involving the mutual interaction of ionospheric scientists, aeronomists, plasma physicists and numerical analysts. During the past six years, members of the center have made seminal contributions to a number of definitive...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
Sporadic and localized interactions of coherent structures arising from plasma resonances can be the origin of "complexity" of the coexistence of non- propagating spatiotemporal fluctuations and propagating modes in space plasmas. Numerical simulation results are presented to demonstrate the intermittent character of the non-propagating fluctuations. The technique of the dynamic renormalization-group is introduced and applied to the study of scale invariance of such type of multiscale...
Topics: NASA Technical Reports Server (NTRS), SPACE PLASMAS, TURBULENCE, NUMERICAL ANALYSIS, PARTICLE...
This annual report contains a detailed description of the activities, accomplishments, and research progress of the MIT Center for Theoretical Geoplasma Physics established under the University Research Initiative Program by AFOSR. During this second phase of the program, the Center has made definite strides toward the goals prescribed in the renewal proposal. The Center has now a staff of twenty-five (25) faculty, research scientists, postdoctoral, graduate and undergraduate students and...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH, *RESEARCH...
The "physics of complexity" in space plasmas is the central theme of this exposition. It is demonstrated that the sporadic and localized interactions of magnetic coherent structures arising from the plasma resonances can be the source for the coexistence of nonpropagating spatiotemporal fluctuations and propagating modes. Non-Gaussian probability distribution functions of the intermittent fluctuations from direct numerical simulations are obtained and discussed. Power spectra and...
Topics: NASA Technical Reports Server (NTRS), ANISOTROPY, INTERMITTENCY, SPACE PLASMAS, TURBULENCE,...
Results of a five-year study of a variety of kinetic plasma processes in the ionosphere and magnetosphere are described. Specific topics discussed in detail include: (1) The formation of ion conics due to electromagnetic ion cyclotron and/or lower hybrid turbulence. (2) Auroral beam-plasma interactions and VLF turbulence, (3) Heating of charged particles in the ionosphere and magnetosphere due to strong plasma turbulence, (4) Formation of counterstreaming electron distributions along auroral...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE, *IONOSPHERE, *MAGNETOSPHERE,...
Partial Contents: Transverse Acceleration and Heating of Ionospheric Ions and the Formation of Ion conics; Transverse Heating of Ionospheric Ions Along Auroral Field Lines; Acceleration of Ionospheric Ions by Lower Hybrid Waves in the Discrete Auroral Region; Two Dimensional Particle-in-cell Plasma Simulation of High-Latitude Lower Hybrid Turbulence and Charged Particle Acceleration; Studies of Inhomogeneous Plasma Turbulence in the Auroral Region; A Kinetic Treatment of the Nonclassical Polar...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE CENTER FOR SPACE RESEARCH,...
Research topics considered include: ionosphere-magnetosphere coupling, high-latitude ionospheric turbulence, charged particle acceleration and heating, nonclassical polar wind, double layers, magnetic reconnection, strong MHD turbulence, plasma radiations induced by moving conducting objects in the low-altitude ionosphere, and F region subvisual polar arcs. Partial Contents: Transverse Acceleration and Heating of Ionospheric Ions and the Formation of Ion Conics: Transverse Heating of...
Topics: DTIC Archive, Chang, Tom, MASSACHUSETTS INST OF TECH CAMBRIDGE, *AURORAE, *MAGNETOHYDRODYNAMICS,...
