Laboratory plasma wave experiments

Stable Maxwellian plasma wave modes, theoretical and experimental treatmen

Theoretical and experimental studies of space-related plasma wave propagation and resonance phenomena

Active research is reported in the following areas: (1) whistler propagation; (2) whistler triggered VLF emissions; (3) Alfven wave excitation; (4) helical electron beams for whistler generation; and (5) ULF excitation by metallic electric or magnetic dipole antennas

Theoretical and experimental studies of the nature and characteristics of space related plasma resonance phenomena

Theoretical and experimental studies of space related plasma wave propagation and resonance phenomena cover whistler emissions and instabilities, low frequency plasma instabilities, nonlinear wave interactions and scattering from plasma column, and the resonance come of dipole antenna immersed in cold overdense magnetoplasma

Computational study of nonlinear plasma waves: 1: Simulation model and monochromatic wave propagation

An economical low noise plasma simulation model is applied to a series of problems associated with electrostatic wave propagation in a one-dimensional, collisionless, Maxwellian plasma, in the absence of magnetic field. The model is described and tested, first in the absence of an applied signal, and then with a small amplitude perturbation, to establish the low noise features and to verify the theoretical linear dispersion relation at wave energy levels as low as 0.000,001 of the plasma thermal energy. The method is then used to study propagation of an essentially monochromatic plane wave. Results on amplitude oscillation and nonlinear frequency shift are compared with available theories. The additional phenomena of sideband instability and satellite growth, stimulated by large amplitude wave propagation and the resulting particle trapping, are described

The Impact of Agricultural Technology in Sub-Saharan Africa: A Synthesis of Symposium Findings

The Symposium on the Impact of Technology on Agricultural Transformation in Sub-Saharan Africa funded by AID/AFR/ARTS and AID/RD/EID under the Michigan State University Food Security Cooperative Agreements, was held in Washington, D.C., Oct. 14-16, 1992. A primary purpose of the symposium was to present evidence which would either confirm or contradict the perception that the accomplishments of TDT were insufficient to justify continued funding. A secondary objective was to consider the adequacy of available analytical tools for impact assessment. The rate of return (ROR) is the most commonly used valuative measure of investments in technology development and transfer. Examined as a group, the estimated RORs support the proposition that African agricultural research has had people-level impacts, and that these impacts are large enough to justify the level of investment that led to the impacts. An important part of the impact assessment story is the analysis of factors that had a positive or negative effect on the impact of TDT. Five major factors emerged from the studies presented and comments by symposium participants: agroclimatic conditions, civil unrest, research system performance, policy, and markets. Progress has been made in moving forward with the process of TDT, in spite of adverse conditions. This progress includes enhancing the capabilities of national, regional and international institutions to generate new techniques, pushing forward the technology frontier, transferring technology, and increasing productivity both in farm production and post-harvest activities. Activities such as structural adjustment, improvements in agricultural and macroeconomic policy, greater reliance on democracy and capitalism, investments in infrastructure, and a greater willingness to work with the private sector have increased the potential for TDT to have significant impact. Given the importance of raising productivity in agriculture as a step towards agricultural transformation, continued investment in agricultural TDT is merited. The evidence of impact achieved from previous investments shows that those investments have paid off. Coupled with the evidence of beneficial changes in the macroeconomic policy environment in many countries, this provides the basis for expecting that future investments will pay off. What is perhaps unique about the symposium is the movement towards a commodity sector perspective as the next logical step toward including more demand-side considerations in the TDT agenda.International Development, Research and Development/Tech Change/Emerging Technologies, Downloads July 2008 - June 2009: 18,

Parametric wave amplification and mixing in the ionosphere

Parametric wave amplification and mixing in ionospher