scholarly journals In Situ Exploration of Particle Simulations with CPU Ray Tracing

2016 ◽  
Vol 3 (4) ◽  
Keyword(s):  
Ray Tracing ◽  
Particle Simulations

Transport of energetic particles from reconnecting current sheets in flaring corona to the heliosphere

2021 ◽  
Author(s):  
Philippa Browning ◽  
Mykola Gordovskyy ◽  
Satashi Inoue ◽  
Eduard Kontar ◽  
Kanya Kusano ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Energetic Particles ◽  
Transport Processes ◽  
Data Driven ◽  
Current Sheets ◽  
Electrons And Ions ◽  
Data Driven Approach ◽  
Particle Simulations ◽  
The Magnetic Field

<p>In this study, we inverstigate the acceleration of electrons and ions at current sheets in the flaring solar corona, and their transport into the heliosphere. We consider both generic solar flare models and specific flaring events with a data-driven approach. The aim is to answer two questions: (a) what fraction of particles accelerated in different flares can escape into the heliosphere?; and (b) what are the characteristics of the particle populations propagating towards the chromosphere and into the heliosphere?</p><p>We use a combination of data-driven 3D magnetohydrodynamics simulations with drift-kinetic particle simulations to model the evolution of the magnetic field and both thermal and non-thermal plasma and to forward-model observable characteristics. Particles are accelerated in current sheets associated with flaring reconnection. When applied to a specific flare, the model successfully predicts observed features such as the location and relative intensity of hard X-ray sources and helioseismic source locations. This confirms the viability of the approach.</p><p>Using these MHD-particle models, we will show how the magnetic field evolution and particle transport processes affect the characteristics of both energetic electrons and ions in the the inner corona and the heliosphere. The implications for interpretation of in situ measurements of energetic particles by Solar Orbiter and Parker Solar Probe will be discussed.</p><p> </p><p> </p>

Effect of the equivalent refractive index on intraocular lens power prediction with ray tracing after myopic laser in situ keratomileusis

2015 ◽  
Vol 41 (5) ◽  
pp. 1030-1037 ◽  
Author(s):  
Carmen Canovas ◽  
Marrie van der Mooren ◽  
Robert Rosén ◽  
Patricia A. Piers ◽  
Li Wang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Ray Tracing ◽  
Intraocular Lens ◽  
Laser In Situ Keratomileusis ◽  
Power Prediction ◽  
Intraocular Lens Power ◽  
Lens Power

Validation of tropospheric ties at the test setup GNSS co-location site in Potsdam

2021 ◽  
Author(s):  
Chaiyaporn Kitpracha ◽  
Robert Heinkelmann ◽  
Markus Ramatschi ◽  
Kyriakos Balidakis ◽  
Benjamin Männel ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Reference Frames ◽  
Meteorological Data ◽  
In Situ Measurements ◽  
Zenith Delay ◽  
Terrestrial Reference Frames ◽  
Space Geodetic Techniques ◽  
Set Up ◽  
Weather Models

<p>Atmospheric ties are induced by differences between the set-up of observing geodetic systems at co-location sites, are mainly attributed to frequency and position, and are usually quantified by zenith delay and gradient component offsets derived by weather models or in situ instuments.. Similar to local ties, they could be applied to combine datasets from several space geodetic techniques, thus contributing to the improvement of the realization of terrestrial reference frames (TRF). Theoretically, atmospheric ties are affected only by the height differences between antennas at the same site and meteorological conditions. Therefore, atmospheric ties could be determined analytically based on meteorological information from in situ measurements or weather models. However, there is often a discrepancy between the expected zenith delay differences and those estimated from geodetic analysis, potentially degrading a combined atmospheric ties solution should tight constraints be used. In this study, we set up a GNSS experiment campaign on the rooftop of a building in Telegrafernberg that offers unobscured data coverage for one month. We compared the estimated zenith delay and gradients from GNSS stations in this experiment, applying atmospheric ties from (1) meteorological data from the Global Pressure and Temperature model 3 (GPT3), (2) ERA5 reanalysis, and (3) in-situ measurements, as well as corrections derived from ray tracing (Potsdam Mapping Functions, PMF). The results show that atmospheric ties employing GPT3, ERA5, in-situ measurements, and ray tracing has an excellent and comparable performance in term of bias mitigation, but not in term of standard deviation, for zenith delay. Moreover, the unexpected bias in zenith delay was identified in the antenna with radome installation. A significantly large bias was identified in estimated gradients; the source of this discrepancy has been traced back to unmitigated multipath effects in this experiment.</p>

Optical ray tracing–guided laser in situ keratomileusis for moderate to high myopic astigmatism

2012 ◽  
Vol 38 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Silvia Schumacher ◽  
Theo Seiler ◽  
Arthur Cummings ◽  
Matthias Maus ◽  
Michael Mrochen
Keyword(s):  
Ray Tracing ◽  
Laser In Situ Keratomileusis ◽  
Myopic Astigmatism ◽  
Optical Ray Tracing ◽  
High Myopic Astigmatism

scholarly journals Characteristics and sources of gravity waves observed in NLC over Norway

2013 ◽  
Vol 13 (11) ◽  
pp. 29303-29331
Author(s):  
T. D. Demissie ◽  
P. J. Espy ◽  
N. H. Kleinknecht ◽  
M. Hatlen ◽  
N. Kaifler ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Gravity Waves ◽  
Source Region ◽  
Digital Camera ◽  
Coastal Region ◽  
Primary Source ◽  
Noctilucent Cloud ◽  
The North ◽  
The Waves

Abstract. Four years of noctilucent cloud (NLC) images from an automated digital camera in Trondheim and results from a ray tracing model are used to extend the climatology of gravity waves to higher latitudes and to identify their sources at high latitudes during summertime. The climatology of the summertime gravity-waves detected in NLC between 64° and 74° N is similar to that observed between 60° and 64° N by Pautet et al. (2011). The direction of propagation of gravity waves observed in the NLC north of 64° N is a continuation of the north and northeast propagation as observed in south of 64° N. However, a unique population of fast, short wavelength waves propagating towards the SW is observed in the NLC, which is consistent with transverse instabilities generated in-situ by breaking gravity waves (Fritts et al., 2003). The relative amplitude of the waves observed in the NLC Mie-scatter have been combined with ray-tracing results to show that waves propagating from near the tropopause, rather than those resulting from secondary generation in the stratosphere or mesosphere, are more likely to be the sources of the prominent wave structures observed in the NLC. The coastal region of Norway along the latitude of 70° N is identified as the primary source region of the waves generated near the tropopause.

scholarly journals Characteristics and sources of gravity waves observed in noctilucent cloud over Norway

2014 ◽  
Vol 14 (22) ◽  
pp. 12133-12142 ◽  
Author(s):  
T. D. Demissie ◽  
P. J. Espy ◽  
N. H. Kleinknecht ◽  
M. Hatlen ◽  
N. Kaifler ◽  
...  
Keyword(s):  
Ray Tracing ◽  
Gravity Waves ◽  
Source Region ◽  
Digital Camera ◽  
Coastal Region ◽  
Primary Source ◽  
Noctilucent Cloud ◽  
The North ◽  
The Waves

Abstract. Four years of noctilucent cloud (NLC) images from an automated digital camera in Trondheim and results from a ray-tracing model are used to extend the climatology of gravity waves to higher latitudes and to identify their sources during summertime. The climatology of the summertime gravity waves detected in NLC between 64 and 74° N is similar to that observed between 60 and 64° N by Pautet et al. (2011). The direction of propagation of gravity waves observed in the NLC north of 64° N is a continuation of the north and northeast propagation as observed in south of 64° N. However, a unique population of fast, short wavelength waves propagating towards the SW is observed in the NLC, which is consistent with transverse instabilities generated in situ by breaking gravity waves (Fritts and Alexander, 2003). The relative amplitude of the waves observed in the NLC Mie scatter have been combined with ray-tracing results to show that waves propagating from near the tropopause, rather than those resulting from secondary generation in the stratosphere or mesosphere, are more likely to be the sources of the prominent wave structures observed in the NLC. The coastal region of Norway along the latitude of 70° N is identified as the primary source region of the waves generated near the tropopause.

Geometric Ray Tracing for Design of Customized Ablation in Laser in situ Keratomileusis

2002 ◽  
Vol 18 (3) ◽  
Author(s):  
Dolores Ortiz ◽  
José M Saiz ◽  
Francisco González ◽  
José N Fernández Del Cotero ◽  
Fernando Moreno
Keyword(s):  
Ray Tracing ◽  
Laser In Situ Keratomileusis
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