scholarly journals 74. The distribution of meteor masses

1957 ◽  
Vol 4 ◽  
pp. 392-393
Author(s):  
I. C. Browne ◽  
K. Bullough ◽  
S. Evans ◽  
T. R. Kaiser
Keyword(s):  
Mass Distribution ◽  
Ionization Process ◽  
Line Density ◽  
Simple Theories ◽  
Electron Line ◽  
Statistical Studies ◽  
Meteor Trails ◽  
Image Position

Kaiser (1953) [1] has shown how it is possible, from statistical studies of radio echoes from meteor trails, to obtain values of the exponent s in the assumed equation for the number of meteors n(α) of line density α where αm is the maximum electron line density (number of electrons per cm.) produced in the trail of a meteor. If the simple theories of the meteor ionization process are correct, αm is proportional to the meteor mass m, so that from radio echo studies it should be possible to obtain a measure of the meteor mass distribution: where n(m) is the number of meteors with mass in the range from m to m + dm.

scholarly journals Ablation in Meteors

1971 ◽  
Vol 13 ◽  
pp. 259-269
Author(s):  
V. N. Lebedinets
Keyword(s):  
Physical Theory ◽  
Line Density ◽  
Radar Observations ◽  
Electron Line ◽  
Ablation Mechanism ◽  
Meteor Trail ◽  
Meteor Trails

Photographic and Radar Observations of meteors reveal essential discrepancies from the simplest physical theory of meteors. The simplest theory (Whipple, 1943; Herlofson, 1948; Kascheev et al., 1967) proceeds from the following suppositions: (1) the meteoroid is a dense non-fragmenting body; (2) the sole ablation mechanism is evaporation; and (3) the whole energy transferred to a body by colliding air molecules is spent on evaporation. In addition, the simplest theory of radiowave reflection from meteor trails that does not take into account diffusive and thermodiffusive expansion of a meteor trail and change of the electron line density along the trail is used for the interpretation of the results of radar observations.

scholarly journals 34. Meteor mass distribution from underdense-trail echoes

1968 ◽  
Vol 33 ◽  
pp. 362-372 ◽  
Author(s):  
M. Šimek ◽  
B.A. McIntosh
Keyword(s):  
High Power ◽  
Statistical Error ◽  
Total Sample ◽  
Logarithmic Scale ◽  
Line Density ◽  
A Value ◽  
Electron Line ◽  
The Mean ◽  
Image Position

The amplitude of meteor echoes is recorded on a logarithmic scale by a high-power radar equipment (λ = 9·2 m, PT=3 MW, G = 5·6) at Springhill Meteor Observatory near Ottawa. The smallest amplitude measured corresponds to a pulse power of 10−12 W, which represents a minimum electron line density of about 7 × 1011 el/m or a radio magnitude of + 10.Distribution curves of number of echoes as a function of echo power have been obtained from some 50 samples of 500 meteors each, at various times of day on about 1 day per month. The slopes showed little variation throughout the year. The statistical error in the slope value for any one sample was small, ~ 2–3%. However, determination of the mass index s from these slopes involves several problems. On the basis of simplest theory we have obtained for the sporadic background, with no definite seasonal or diurnal variation.During shower periods, lower values of s were obtained. For the 1966 Leonids, s for the shower was determined by estimating the percentage of shower meteors in the total sample. A value s = 1·7 ± 0·1 was obtained as the mean of 6 samples. It is not known to what extent the height-ceiling effect influences the observation of this shower.

Mathematical Notes by Professor Tait (2.) On the Equipotential Surfaces for a Straight Wire

1875 ◽  
Vol 8 ◽  
pp. 443-443
Keyword(s):  
Natural Philosophy ◽  
Line Density ◽  
Straight Wire ◽  
Equipotential Surfaces ◽  
The Wire ◽  
Image Position

Some results given in Vol. I. of Thomson and Tait's Natural Philosophy may be much more simply obtained by calculating the potential of a wire rather than its attraction. That potential is easily found aswhere c is the length of the wire, ρ its line density, r1 and r2 the distances of its ends from the point at which the potential is to be found.

Ionization profile of meteors from simultaneous video and radio forward scatter observations

2020 ◽  
Author(s):  
Hervé Lamy ◽  
Michel Anciaux ◽  
Sylvain Ranvier ◽  
Antoine Calegaro ◽  
Carl Johannink
Keyword(s):  
Peak Power ◽  
Specular Reflection ◽  
Radio Waves ◽  
Line Density ◽  
Science And Engineering ◽  
Forward Scatter ◽  
Electron Line ◽  
Power Profile ◽  
Video Observations ◽  
Polarization Factor

<p>In this study, optical video observations of meteors with the CAMS (Camera for All-sky Meteor Surveillance)-BeNeLux network and radio forward scatter observations with the BRAMS (Belgian RAdio Meteor Stations) network obtained on 4-5 October 2018  are combined in order to obtain an ionization profile along a meteor path.</p><p>The trajectory, initial speed and deceleration parameters of a given meteor are provided by the CAMS-BeNeLux data. For a given trajectory, the positions of the specular reflection points for radio waves are computed for each combination of a given BRAMS receiving station and the BRAMS transmitter. For each receiving station which recorded a meteor echo (depending on the geometry and the SNR ratio), the power profile is computed and the peak power values of the underdense meteor profiles are used to determine the ionization (electron line density) at the various specular reflection points along the meteor path. This is done using the McKinley (1961) formula which is strictly valid for underdense meteor echoes.  We discuss how we compute the gains of the antennas, the polarization factor, and how the peak power values are transformed from arbitrary units into watts using the signal recorded from a device called the BRAMS calibrator. We also discuss how to extend this study to overdense meteor echoes or those with intermediate electron line densities.</p><p>Finally, these results are combined with a simple ablation meteor model in order to obtain an estimate of the initial mass of the meteoroid.</p><p>Mc Kinley D.W.R., Meteor science and engineering, Mc Graw-Hill eds, 1961</p>

Measurement of radio-meteor ionization profiles

1969 ◽  
Vol 47 (14) ◽  
pp. 1467-1473 ◽  
Author(s):  
J. Jones
Keyword(s):  
Ambipolar Diffusion ◽  
Line Density ◽  
Automatic Determination ◽  
Density Profiles ◽  
Electron Line ◽  
Cosmic Noise

The theory of a method for the determination of electron line density profiles of underdense radio meteors is developed, and the effects of cosmic noise, winds in the meteor region, and ambipolar diffusion on the measured profiles are estimated. The design of a device for the automatic determination of radiometeor ionization profiles is described, together with some results obtained using it in conjunction with the Ottawa–London (Ontario) backscatter system.

Measurement of the free electron line density in a spherical theta-pinch plasma target by single wavelength interferometry

2021 ◽  
Author(s):  
Philipp Christ ◽  
Konstantin Cistakov ◽  
Marcus Iberler ◽  
Layla Laghchioua ◽  
Dominic Mann ◽  
...  
Keyword(s):  
Free Electron ◽  
Line Density ◽  
Pinch Plasma ◽  
Theta Pinch ◽  
Electron Line ◽  
Plasma Target

Mass distribution of peptide molecular ions in the secondary ionization process

1985 ◽  
Vol 63 (2-3) ◽  
pp. 231-240 ◽  
Author(s):  
Y. Fujita ◽  
T. Matsuo ◽  
T. Sakurai ◽  
H. Matsuda ◽  
I. Katakuse
Keyword(s):  
Mass Distribution ◽  
Molecular Ions ◽  
Ionization Process

A Note on Upper Bounds for the Eigenvalues ofy″ + λpy=0

1975 ◽  
Vol 18 (3) ◽  
pp. 347-351
Author(s):  
Rodney D. Gentry
Keyword(s):  
Differential Equation ◽  
Boundary Condition ◽  
Mass Distribution ◽  
Unit Length ◽  
Upper Bounds ◽  
Natural Modes ◽  
Negative Function ◽  
Modes Of Vibration ◽  
Image Position ◽  
System 1

The natural modes of a small planar transversal vibration of a fixed string of unit length and tension are determined by the eigenvalues and associated eigenfunctions of the differential equation(1)subject to the boundary condition(2)where the non-negative functionpdescribes the mass distribution of the string. That the distribution of mass on the string influences the modes of vibration, may be reflected by observing that the eigenvalues determined by the system (1–2) may be considered functions of the densityp, λn(p), where λ1(p)<λ2(p)<….

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