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Title: CALCULATIONS OF SHAPE CHANGE AND FRAGMENTATION PARAMETERS USING VERY PRECISE BOLIDE DATA

Abstract

No abstract prepared.

Authors:
Publication Date:
Research Org.:
Los Alamos National Lab., NM (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
788215
Report Number(s):
LA-UR-01-5653
TRN: US200202%%281
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Oct 2001
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; FRAGMENTATION; METEORITES; METEOROIDS; MORPHOLOGICAL CHANGES; CALCULATION METHODS

Citation Formats

D. O. REVELLE. CALCULATIONS OF SHAPE CHANGE AND FRAGMENTATION PARAMETERS USING VERY PRECISE BOLIDE DATA. United States: N. p., 2001. Web.
D. O. REVELLE. CALCULATIONS OF SHAPE CHANGE AND FRAGMENTATION PARAMETERS USING VERY PRECISE BOLIDE DATA. United States.
D. O. REVELLE. Mon . "CALCULATIONS OF SHAPE CHANGE AND FRAGMENTATION PARAMETERS USING VERY PRECISE BOLIDE DATA". United States. doi:. https://www.osti.gov/servlets/purl/788215.
@article{osti_788215,
title = {CALCULATIONS OF SHAPE CHANGE AND FRAGMENTATION PARAMETERS USING VERY PRECISE BOLIDE DATA},
author = {D. O. REVELLE},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 01 00:00:00 EDT 2001},
month = {Mon Oct 01 00:00:00 EDT 2001}
}

Conference:
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  • Using the theoretical formalism of ReVelle (2001d), we have analyzed 22 European (EN) and US Prairie Network fireballs (PN) with the most precise trajectory information available for shape change and fragmentation effects. For 14 bolides the shape change parameter, {mu}, was always > 0 and for the other 8 cases there were instances of {mu} < 0, but with large oscillations in its sign with height or time. When the shape change parameter, {mu}, was < 0, the fragmentation scale height was > 0 and in a few instances was briefly even smaller than the pressure scale height. This ismore » the necessary condition in addition to the sufficient condition of {mu} < 0 for the onset of the catastrophic fragmentation process ('pancake' break-up). A histogram of all computed {mu} values indicates that an average value was <{mu} > {approx} 0.10, indicating that substantial shape change has taken place during entry for these bolides. This is fully consistent with the recent analyses of ReVelle and Ceplecha (2001g) of the changes in the shape-density coefficient, K, with time as well. Thus, the use of the {mu} = 2/3 (self-similar solution with no shape change) is not recommended for bolide modeling efforts. From our results we can conclude that most of the US DoD bolides can be successfully modeled using single-body theory without resorting to the 'pancake' catastrophic fragmentation model that was 'rediscovered' in the early 1990's by a number of workers. These researchers included Hills and Goda, Chyba, Thomas and Zahnle, etc. who specifically developed this break-up model for studying he impact into Jupiter of the huge Shoemaker Levy-9 comet.« less
  • The catastrophic 'pancake' fragmentation process, proposed as being generally applicable to very large meteoroid entry in the early 1990's by a number of workers, has been carefully examined. In this effort, the transition from the traditional single-body dynamics and energetics model to a catastrophic 'pancake' fragmentation process has been delineated. The key parameters are the {mu} parameter originally proposed by Levin and the fragmentation scale height, Hf, which we have derived from {mu}. It has been found that this break-up process can only occur for an optimum set of circumstances.
  • An instrument which will measure the atmospheric concentration of carbon dioxide with a resolution of one part in 10{sup 4} will be realized in the framework of Environment and Climate program of the European Community. The aims are the evaluation of global climate changes and the measurement of the flux at the interface air-sea. The requirements for such an instrument apart from resolution are stability and insensitivity to water. This instrument is based on room temperature tunable diode lasers at about 6,350 cm{sup {minus}1}, a frequency region free from water absorptions, but only recently covered by laser sources with themore » required spectral characteristics. The atmospheric concentration of carbon dioxide is about 350 ppm and its absorbance along a path of 100 m is of the order of 1%. The measurement will be performed in a multipass cell. A second cell will supply the references for frequency stabilization and laser power monitoring. The detection is realized through frequency modulation techniques. The various aspects of the work presently in progress will be presented: spectroscopy, optical layout, detection method and so on.« less