NASA Scientific and Technical Aerospace Reports

calculating power generation and usage (power-flow, power contingencies, specific power). The report represents a general
consensus of the nuclear fusion space propulsion system conceptual design community and proposes 15 recommendations.
This paper expands on the Report by providing specific examples illustrating how to apply each of the recommendations.
Author
Design Analysis; Nuclear Fusion; Propulsion
20040112050 NASA Glenn Research Center, Cleveland, OH, USA
An Operator Method for Field Moments from the Extended Parabolic Wave Equation and Analytical Solutions of the
First and Second Moments for Atmospheric Electromagnetic Wave Propagation
Manning, Robert M.; [2004]; 21 pp.; In English
Contract(s)/Grant(s): WBS 22-302-20-2F; No Copyright; Avail: CASI; A03, Hardcopy
The extended wide-angle parabolic wave equation applied to electromagnetic wave propagation in random media is
considered. A general operator equation is derived which gives the statistical moments of an electric field of a propagating
wave. This expression is used to obtain the first and second order moments of the wave field and solutions are found that
transcend those which incorporate the full paraxial approximation at the outset. Although these equations can be applied to
any propagation scenario that satisfies the conditions of application of the extended parabolic wave equation, the example of
propagation through atmospheric turbulence is used. It is shown that in the case of atmospheric wave propagation and under
the Markov approximation (i.e., the delta-correlation of the fluctuations in the direction of propagation), the usual parabolic
equation in the paraxial approximation is accurate even at millimeter wavelengths. The comprehensive operator solution also
allows one to obtain expressions for the longitudinal (generalized) second order moment. This is also considered and the
solution for the atmospheric case is obtained and discussed. The methodology developed here can be applied to any qualifying
situation involving random propagation through turbid or plasma environments that can be represented by a spectral density
of permittivity fluctuations.
Author
Electromagnetic Wave Transmission; Wave Propagation; Atmospheric Turbulence; Wave Equations
20040120850 Stanford Linear Accelerator Center, Stanford, CA, USA
Direct Measurement of A(sub b) in Z(sup 0) Decays Using Charged Kaon Tagging
Dec. 1998; 14 pp.; In English
Report No.(s): DE2004-9928; SLAC-PUB-7959; No Copyright; Avail: Department of Energy Information Bridge
We present a direct measurement of the parity-violating asymmetry A(sub b) in the Z(sup 0) to b anti-b coupling using
a new technique to distinguish the b and anti-b quarks using charged kaons from B decays. The Z(sup 0) bosons are produced
in e(sup+)e(sup -) collisions at the SLC with longitudinally polarized electrons. b anti-b events are selected using a secondary
vertex mass tag and A(sub b) is determined from the left-right forward-backward asymmetry. From the 1994-1995 data
sample, selected from 100,000 hadronic Z(sup 0) decays, we obtain A(sub b)= 0.855(+-) 0. 088(sub stat)(+-) 0. 102(sub sys).
NTIS
Particle Decay; Asymmetry; Quarks; Kaons
20040120852 Fermi National Accelerator Lab., Batavia, IL, USA
pH and Resistivity of the BCP Mix Diluted in UPW
Boffo, C.; Connolly, D.; Hicks, D.; Hoffman, J.; May 2004; 18 pp.; In English
Report No.(s): DE2004-823614; FERMILAB-TM-2233; No Copyright; Avail: Department of Energy Information Bridge
Etching plays an important role in the production of superconducting cavities (SRF). As other laboratories engaged in RF
superconductivity R and D did, FNAL is also developing a facility for the chemical etching of niobium (Nb) cavities. Two
techniques are common accepted for cavity etching: (1) chemical etching--buffered chemical polishing (BCP); and (2)
Electropolishing (EP). Among them, at FNAL it was decided to pursue chemical etching, which is considered a reliable
technique tested by several labs for many years. In the past, numerous mixtures of acids have been tested leading to the actual
buffered chemical polishing mix (BCP) characterized by the following composition by volume: 1 of HF 49 %wt; 1 of
HNO(sub 3) 69.5 %wt; 2 of H(sub 3)PO(sub 4) 85 %wt. Because of the dangerous nature of the chemicals involved, safety
considerations require the development of a proper process and a reliable control algorithm. For the post-processing rinsing
of the cavities, one needs to know the expected pH of the water used to rinse the cavity. On the other hand, for early detection
of leaks in the hydraulic system, which is done by measuring the conductivity of the rinsing water used in the process, one
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