Link Budget Analysis with Laser Energy for Time Transfer Using the Ajisai Satellite

Two-way Laser Time Transfer (TLTT) using the Ajisai satellite has been considered as a more accurate and stable time transfer technique than existing methods; TLTT requires the kHz laser pulses to decrease the systematic restrictions for TLTT realization. However, because of the low energy of the kHz laser pulses as well as the low cross section due to the small size of the Ajisai reflecting mirror, the link budget is an important issue to establish the TLTT link between two ground stations. In this study, the TLTT link budget is investigated to find the optimal laser pulse energy via analysis of geometric effects using 30 days of orbital data of the Ajisai satellite from 29 March 2021 within a ground network consisting of four stations located in three countries. The geometric configuration reduces the TLTT link budget by three orders of magnitude due to free space loss, atmospheric transmission, and effective cross section; then, the pulse energy is required to be much higher than laser ranging to the Ajisai satellite. It is shown from the simulation that a few tens of mJ level of pulse energy at the transmitting station is quite enough for TLTT realization.

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EFFECTS OF SPACE CHARGE ON THE "EFFECTIVE CROSS SECTION"

Le Journal de Physique Colloques ◽

10.1051/jphyscol:19797365 ◽

1979 ◽

Vol 40 (C7) ◽

pp. C7-755-C7-756

Author(s):

N. S. Kopeika ◽

T. Karcher ◽

C.S. Ih.

Keyword(s):

Space Charge ◽

Cross Section ◽

Effective Cross Section

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Proton structure in transverse space and the effective cross section

Physical Review D ◽

10.1103/physrevd.60.054023 ◽

1999 ◽

Vol 60 (5) ◽

Cited By ~ 47

Author(s):

G. Calucci ◽

D. Treleani

Keyword(s):

Cross Section ◽

Effective Cross Section ◽

Proton Structure

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Link budget analysis of free space optical communication link for atmospheric conditions of India

Materials Today Proceedings ◽

10.1016/j.matpr.2021.07.188 ◽

2021 ◽

Author(s):

Harjeevan Singh ◽

Nitin Mittal

Keyword(s):

Optical Communication ◽

Free Space ◽

Communication Link ◽

Free Space Optical Communication ◽

Atmospheric Conditions ◽

Free Space Optical ◽

Budget Analysis ◽

Space Optical Communication ◽

Link Budget

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Min-Max Criterion for Global Link Budget Analysis of Digital Channelized SATCOM System and Classical Transponder System

IEEE Transactions on Aerospace and Electronic Systems ◽

10.1109/taes.2012.6237618 ◽

2012 ◽

Vol 48 (3) ◽

pp. 2679-2689 ◽

Cited By ~ 1

Author(s):

Zhiming Yang ◽

Zhigang Cao

Keyword(s):

Budget Analysis ◽

Link Budget

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The study of neutron capture processes in AlN nanoparticles

International Journal of Modern Physics B ◽

10.1142/s0217979221501277 ◽

2021 ◽

pp. 2150127

Author(s):

T. G. Naghiyev

Keyword(s):

Computer Modeling ◽

Cross Section ◽

Neutron Capture ◽

Absorption Cross Section ◽

Effective Cross Section ◽

Absorption Cross ◽

Effective Absorption ◽

Different Types ◽

N Isotopes

The neutron capture processes in the AlN nanoparticles were investigated by computer modeling. Neutrons absorption were separately investigated for aluminum (Al) and nitrogen (N) atoms in the AlN nanoparticles. The modeling was performed separately for each stable Al and N isotopes, because the effective absorption cross-section of different types of isotopes of Al and N atoms is different. Moreover, effective cross-section spectra of neutron capture for aluminum and nitrogen atoms were comparatively investigated.

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Nonperturbative generation of above-threshold harmonics from pre-excited argon atoms in intense mid-infrared laser fields

High Power Laser Science and Engineering ◽

10.1017/hpl.2017.26 ◽

2017 ◽

Vol 5 ◽

Cited By ~ 2

Author(s):

Guihua Li ◽

Hongqiang Xie ◽

Ziting Li ◽

Jinping Yao ◽

Wei Chu ◽

...

Keyword(s):

Excited State ◽

Femtosecond Laser ◽

Pulse Energy ◽

Laser Pulses ◽

Infrared Laser ◽

Femtosecond Laser Pulses ◽

Probe Laser ◽

Laser Fields ◽

Mid Infrared ◽

Highly Nonlinear

We experimentally investigate the generation of above-threshold harmonics completely from argon atoms on an excited state using mid-infrared femtosecond laser pulses. The highly nonlinear dependences of the observed signal on the pulse energy and polarization of the probe laser pulses indicate its nonperturbative characteristic.

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Magnetically induced termination of giant planet formation

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833611 ◽

2018 ◽

Vol 619 ◽

pp. A165 ◽

Cited By ~ 7

Author(s):

A. J. Cridland

Keyword(s):

Magnetic Field ◽

Cross Section ◽

Planet Formation ◽

Giant Planet ◽

Effective Cross Section ◽

Cold Start ◽

Population Synthesis ◽

Hot Start ◽

Gas Accretion ◽

Planetary Magnetic Field

Here a physical model for terminating giant planet formation is outlined and compared to other methods of late-stage giant planet formation. As has been pointed out before, gas accreting into a gap and onto the planet will encounter the planetary dynamo-generated magnetic field. The planetary magnetic field produces an effective cross section through which gas is accreted. Gas outside this cross section is recycled into the protoplanetary disk, hence only a fraction of mass that is accreted into the gap remains bound to the planet. This cross section inversely scales with the planetary mass, which naturally leads to stalled planetary growth late in the formation process. We show that this method naturally leads to Jupiter-mass planets and does not invoke any artificial truncation of gas accretion, as has been done in some previous population synthesis models. The mass accretion rate depends on the radius of the growing planet after the gap has opened, and we show that so-called hot-start planets tend to become more massive than cold-start planets. When this result is combined with population synthesis models, it might show observable signatures of cold-start versus hot-start planets in the exoplanet population.

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The Effect of Boundary Layer Separation on Accuracy of Flow Measurement Using the Gibson Method

Volume 2: Fora, Parts A and B ◽

10.1115/fedsm2007-37564 ◽

2007 ◽

Cited By ~ 1

Author(s):

F. Z. Sierra ◽

A. Adamkowski ◽

G. Urquiza ◽

J. Kubiak ◽

H. Lara ◽

...

Keyword(s):

Boundary Layer ◽

Cross Section ◽

Flow Rate ◽

Pressure Difference ◽

Proper Time ◽

Effective Cross Section ◽

Boundary Layer Separation ◽

Water Hammer ◽

Time Interval ◽

Geometry Factor

The Gibson method utilizes the effect of water hammer phenomenon (hydraulic transients) in a pipeline for flow rate determination. The method consists in measuring a static pressure difference, which occurs between two cross-sections of the pipeline as a result of a temporal change of momentum from t0 to t1. This condition is induced when the water flow in the pipeline is stopped suddenly using a cut-off device. The flow rate is determined by integrating, within a proper time interval, the measured pressure difference change caused by the water hammer (inertia effect). However, several observations demonstrate that changes of pipeline geometry like diameter change, bifurcations, or direction shift by elbows may produce an effect on the computation of the flow rate. The paper focuses on this effect. Computational simulations have shown that the boundary layer separates when the flow faces sudden changes like these mentioned to above. The separation may reduce the effective cross section area of flow modifying a geometry factor involved into the computation of the flow rate. The remainder is directed to quantify the magnitude of such a factor under the influence of pipeline geometry changes. Results of numerical computations are discussed on the basis of how cross section reductions impact on the geometry factor magnitude and consequently on the mass flow rate.

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