Decay of the O I λ5577 line in meteor wakes

1970 ◽  
Vol 48 (9) ◽  
pp. 1017-1025 ◽  
Author(s):  
W. A. Gault
Keyword(s):  
Decay Rate ◽  
Atomic Oxygen ◽  
Line Emission ◽  
Maximum Intensity ◽  
Time Interval ◽  
Green Line ◽  
Multiple Exposure ◽  
Natural Rate ◽  
Quenching Mechanisms ◽  
Two Parameters

Multiple-exposure spectra of six meteors showing the auroral green line of atomic oxygen have been measured photometrically. The decay of the green line is described in terms of two parameters which are given as functions of height. It is shown that the maximum intensity occurs after a measurable time interval, which varies from 0.3 s at 115 km to 0.06 s at 105 km and decreases further with decreasing height. The subsequent decay rate is close to the natural rate (1 s−1) of the 1S state above 110 km, but increases with decreasing height to 3 s−1 at 100 km. The height of the green-line emission is consistent with most previous measurements, and corresponds with the height of the atmospheric atomic oxygen layer. The observations do not show a correlation of green-line characteristics with geomagnetic activity. Various possible excitation and quenching mechanisms are discussed.

scholarly journals A method for the intensification of atomic oxygen green line emission by internal gravity waves

2008 ◽  
Vol 113 (A12) ◽  
pp. n/a-n/a ◽  
Author(s):  
T. D. Kaladze ◽  
W. Horton ◽  
T. W. Garner ◽  
J. W. Van Dam ◽  
M. L. Mays
Keyword(s):  
Gravity Waves ◽  
Atomic Oxygen ◽  
Line Emission ◽  
Internal Gravity Waves ◽  
Green Line

scholarly journals Eddy turbulence, the double mesopause, and the double layer of atomic oxygen

2012 ◽  
Vol 30 (1) ◽  
pp. 251-258 ◽  
Author(s):  
M. N. Vlasov ◽  
M. C. Kelley
Keyword(s):  
Oxygen Atom ◽  
Density Distribution ◽  
Atomic Oxygen ◽  
Line Emission ◽  
Local Maximum ◽  
Double Layers ◽  
Green Line ◽  
Height Profile ◽  
Height Range ◽  
The Impact

Abstract. In this study, we consider the impact of eddy turbulence on temperature and atomic oxygen distribution when the peak of the temperature occurs in the upper mesosphere. A previous paper (Vlasov and Kelley, 2010) considered the simultaneous impact of eddy turbulence on temperature and atomic oxygen density and showed that eddy turbulence provides an effective mechanism to explain the cold summer and warm winter mesopause observed at high latitudes. Also, the prevalent role of eddy turbulence in this case removes the strong contradiction between seasonal variations of the O density distribution and the impact of upward/downward motion corresponding to adiabatic cooling/heating of oxygen atoms. Classically, there is a single minimum in the temperature profile marking the location of the mesopause. But often, a local maximum in the temperature is observed in the height range of 85–100 km, creating the appearance of a double mesopause (Bills and Gardner, 1993; Yu and She, 1995; Gusev et al., 2006). Our results show that the relative temperature maximum in the upper mesosphere (and thus the double mesopause) can result from heating by eddy turbulence. According to our model, there is a close connection between the extra temperature peak in the mesosphere and the oxygen atom density distribution. The main feature of the O density height profile produced by eddy turbulence in our model is a double peak instead of a single peak of O density. A rocket experiment called TOMEX confirms these results (Hecht et al., 2004). Applying our model to the results of the TOMEX rocket campaign gives good agreement with both the temperature and oxygen profiles observed. Climatology of the midlatitude mesopause and green line emission shows that the double mesopause and the double layers of the green line emission, corresponding to the double O density height profile, are mainly observed in spring and fall (Yu and She, 1995; Liu and Shepherd, 2006). Further observations of the oxygen atom densities and the double mesopause would improve our understanding of the impact of turbulence on critical mesospheric parameters.

scholarly journals First Ground Observations of OI5577 Green Line Emission over the Taiwan Area

2007 ◽  
Vol 18 (4) ◽  
pp. 843
Author(s):  
Sing-Wei Chiou ◽  
Lin-Ni Hau ◽  
Jan-Bai Nee ◽  
Chun-Sung Jao ◽  
Bo-Jhou Wang ◽  
...  
Keyword(s):  
Line Emission ◽  
Green Line ◽  
Taiwan Area

scholarly journals The dark matter interpretation of the 3.5-keV line is inconsistent with blank-sky observations

Science ◽  
2020 ◽  
Vol 367 (6485) ◽  
pp. 1465-1467 ◽  
Author(s):  
Christopher Dessert ◽  
Nicholas L. Rodd ◽  
Benjamin R. Safdi
Keyword(s):  
Dark Matter ◽  
Emission Line ◽  
Decay Rate ◽  
Milky Way ◽  
Line Emission ◽  
Mass Range ◽  
Sterile Neutrinos ◽  
X Ray ◽  
Upper Limit ◽  
Nearby Galaxies

Observations of nearby galaxies and galaxy clusters have reported an unexpected x-ray emission line around 3.5 kilo–electron volts (keV). Proposals to explain this line include decaying dark matter—in particular, that the decay of sterile neutrinos with a mass around 7 keV could match the available data. If this interpretation is correct, the 3.5-keV line should also be emitted by dark matter in the halo of the Milky Way. We used more than 30 megaseconds of XMM-Newton (X-ray Multi-Mirror Mission) blank-sky observations to test this hypothesis, finding no evidence of the 3.5-keV line emission from the Milky Way halo. We set an upper limit on the decay rate of dark matter in this mass range, which is inconsistent with the possibility that the 3.5-keV line originates from dark matter decay.

scholarly journals Harvesting a remote renewable resource

2020 ◽  
Vol 13 (4) ◽  
pp. 459-480 ◽  
Author(s):  
Thorsten Upmann ◽  
Stefan Behringer
Keyword(s):  
Renewable Resource ◽  
Planning Horizon ◽  
Maximum Intensity ◽  
Time Interval ◽  
Control Approach ◽  
Travelling Time ◽  
Intermediate Time ◽  
Standard Models ◽  
Optimal Control Approach ◽  
Continuous Domain

AbstractIn standard models of spatial harvesting, a resource is distributed over a continuous domain with an agent who may harvest everywhere all the time. For some cases though (e.g., fruits, mushrooms, algae), it is more realistic to assume that the resource is located at a fixed point within that domain so that an agent has to travel in order to be able to harvest. This creates a combined travelling–and–harvesting problem where slower travel implies a lower travelling cost and, due to a later arrival, a higher abundance of the resource at the beginning of the harvesting period; this, though, has to be traded off against less time left for harvesting, given a fixed planning horizon. Possible bounds on the controls render the problem even more intricate. We scrutinise this bioeconomic setting using a two-stage optimal control approach, and find that the agent economises on the travelling cost and thus avoids to arrive at the location of the resource too early. More specifically, the agent adjusts the travelling time so as to be able to harvest with maximum intensity at the beginning and the end of the harvesting period, but may also find it optimal to harvest at a sustainable level, where the harvesting and the growth rate of the stock coincide, in an intermediate time interval.

Note: Excitation of the Auroral Green Line of Atomic Oxygen (^{1}S -> ^{1}D) by N_{2}(A ^{3}Σ_{u}^{+})

1969 ◽  
Vol 157 ◽  
pp. 1023 ◽  
Author(s):  
J. A. Meyer ◽  
D. W. Setser ◽  
D. H. Stedman
Keyword(s):  
Atomic Oxygen ◽  
Green Line

scholarly journals Effects of solar cycle variations on oxygen green line emission rate over Kiso, Japan

2011 ◽  
Vol 63 (8) ◽  
pp. 941-948 ◽  
Author(s):  
Uma Das ◽  
C. J. Pan ◽  
H. S. S. Sinha
Keyword(s):  
Solar Cycle ◽  
Emission Rate ◽  
Line Emission ◽  
Green Line
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