A rocket-borne electrostatic analyzer for measurement of energetic particle flux

A rocket-borne electrostatic analyzer experiment is described. It is used to measure energetic particle flux (0.9 to 14 keV) in the nighttime midlatitude E region. Energetic particle precipitation is believed to be a significant nighttime ionization source, particularly during times of high geomagnetic activity. The experiment was designed for use in the payload of a Nike Apache sounding rocket. The electrostatic analyzer employs two cylindrical parallel plates subtending a central angle of 90 deg. The voltage waveform supplied to the plates is a series of steps synchronized to the spin of the payload during flight. Both positive and negative voltages are provided, extending the detection capabilities of the instrument to both electrons and protons (and positive ions). The development, construction and operation of the instrument is described together with a preliminary evaluation of its performance in a rocket flight

Aeronautical engineering: A special bibliography with indexes, supplement 82, April 1977

This bibliography lists 311 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1977

Organized motion and radiative perturbations in the nocturnal canopy sublayer above an even-aged pine forest

none4sìUsing time series measurements of velocity, carbon dioxide and water vapour concentration, and temperature collected just above a 15 m tall even-aged pine forest, we quantify the role of organized motion on scalar and momentum transport within the nocturnal canopy sublayer (CSL). We propose a framework in which the nocturnal CSL has two end-members, both dominated by organised motion. These end-members represent fully developed turbulent flows at near-neutral or slightly stable stratification and no turbulence for very stable stratification. Our analysis suggests that ramps dominate scalar transport for near-neutral and slightly stable conditions, while linear canopy waves dominate the flow dynamics for very stable conditions. For intermediate stability, the turbulence is highly damped and often dominated by fine scale motions. Co-spectral analysis suggests that ramps are the most efficient net scalar mass-transporting agent while linear canopy waves contribute little to net scalar transport between the canopy and atmosphere for averaging intervals that include complete wave cycles. However, canopy waves significantly contribute to the spectral properties of the scalar time series. Ramps are the most frequently occurring organised motion in the nocturnal CSL for this site. Numerous night-time runs, however, resided between these two end-members. Our analysis suggests that when radiative perturbations are sufficient large (>20 W m-2 in net radiation), the flow can switch from being highly damped fine-scale turbulence to being organized with ramp-like properties. We also found that when ramps are already the dominant eddy motion in the nocturnal CSL, radiative perturbations have a minor impact on scalar transport. Finally, in agreement with previous studies, we found that ramps and canopy waves have comparable length scales of about 30-60 metres. Consequences to night-time flux averaging are also discussed.openCAVA, D.; GIOSTRA, U.; SIQUEIRA, M.; G. G. KATULCava, D.; Giostra, Umberto; Siqueira, M.; G. G., Katu