Prithish Halder | Indian Institute of Astrophysics (original) (raw)
Papers by Prithish Halder
ApJS, 2022
The overall understanding of cosmic dust particles is mainly inferred from the different Earth-ba... more The overall understanding of cosmic dust particles is mainly inferred from the different Earth-based measurements of interplanetary dust particles and space missions such as Giotto, Stardust, and Rosetta. The results from these measurements indicate the presence of a wide variety of morphologically significant dust particles. To interpret the light-scattering and thermal emission observations arising due to dust in different regions of space, it is necessary to generate computer-modeled realistic dust structures of various shapes, sizes, porosity, bulk density, aspect ratio, and material inhomogeneity. The present work introduces a Java package called Rough Ellipsoid Structure Tool (REST), which is a collection of multiple algorithms, that aims to craft realistic rough-surface cosmic dust particles from spheres, superellipsoids, and fractal aggregates depending on the measured bulk density and porosity. Initially, spheres having N d dipoles or lattice points are crafted by selecting random material and space seed cells to generate a strongly damaged structure, rough surface, and poked structure. Similarly, REST generates roughsurface superellipsoids and poked structure superellipsoids from initial superellipsoid structures. REST also generates rough fractal aggregates, which are fractal aggregates having rough-surface irregular grains. REST has been applied to create agglomerated debris, agglomerated debris superellipsoids, and mixed-morphology particles. Finally, the light-scattering properties of the respective applied structures are studied to ensure their applicability. REST is a flexible structure tool that shall be useful for generating various types of dust structures that can be applied to studying the physical properties of dust in different regions of space.
Monthly Notices of the Royal Astronomical Society, 2015
We report the results obtained from the optical polarimetric study of the light scattered by come... more We report the results obtained from the optical polarimetric study of the light scattered by comets C/2013 V1 (Boattini) and 290P/Jager at lower phase angles. The polarimetric observations of two comets have been performed with the 1.04-m Sampurnanand telescope of Aryabhatta Research Institute of observational sciencES near Nainital in India on 2013 December 4 and 5, and on 2014 April 24 using R photometric band (λ = 630 nm, λ = 120 nm). We covered observations in both the pre-and post-perihelion passage of comets C/2013 V1 (Boattini) and 290P/Jager at two phase angles ∼ 13 • and 27 •. The degree of polarization changes from (−1.4 ± 0.3) to (+2.8 ± 0.5) per cent for comet C/2013 V1 (Boattini) and (−1.6 ± 0.5) to (+2.5 ± 0.5) per cent for comet 290P/Jager at phase angles ∼13 • and 27 • , respectively. The change in the physical properties of cometary dust is being well studied from the polarization maps obtained for both the period of observations. It is found that the aperture polarization values are comparable to those of other comets. The variation in the brightness profile of both the comets from the standard canonical nature is also being observed in both the solar and antisolar direction during this phase which suggests the various physical evolutions influencing the cometary comae.
Monthly Notices of the Royal Astronomical Society
We investigate the effect of porosity in the Umov effect for the first time using the aggregate d... more We investigate the effect of porosity in the Umov effect for the first time using the aggregate dust model. The Umov effect is an inverse correlation between the reflectivity (or geometric albedo) of an object and the degree of linear polarization of light scattered by it. Three different types of fractal aggregates: ballistic agglomeration (BA), ballistic agglomeration with one migration (BAM1), and ballistic agglomeration with two migrations (BAM2) having porosities 0.87, 0.74, and 0.64, respectively (which have the same characteristic radius ∼1 μm), are considered in our simulations. Using the multisphere T-matrix (mstm) code, maximum positive polarization (Pmax) and geometric albedo (A) are calculated for three different fractal aggregated structures considering amorphous silicate composition. Then Pmax and A are plotted against each other in logarithmic scale that shows a linear inverse correlation and a strong porosity dependence. This study shows that the porosity of the aggr...
Computer Physics Communications
Monthly Notices of the Royal Astronomical Society
In this work, we introduce a comet dust model that incorporates multiple dust morphologies along ... more In this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard polarization-phase curve observed in several comets in the narrow-band continuum. Following the results from Rosetta/midas and COSIMA, we create high porosity hierarchical aggregates (HA) and low porosity (<10 per cent) Solids in the form of agglomerated debris. We also introduce a moderate porosity structure with solids in the core, surrounded by fluffy aggregates called fluffy solids (FS). We study the mixing combinations, (HA and Solids), (HA and FS), and (HA, FS, and Solids) for a range of power-law index n= 2.0 to 3.0 for different sets of mixing percentage of silicate minerals and carbonaceous materials. Polarimetry of the short period comets 1P/Halley and 67P/Churyumov-Gerasimenko match best with the polarization resulting from the combination ...
Astrophysics and Space Science
We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with... more We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with a wide variation of porosity (P) from 0.57 to 0.98. The computations are performed using the Superposition T-matrix code with BAM2 cluster (P ∼ 0.57 − 0.64), BAM1 cluster (P ∼ 0.74), BA or BPCA cluster (P ∼ 0.85 − 0.87) and BCCA cluster (P ∼ 0.98). The simulations are executed at two wavelengths 0.45µm and 0.65µm with highly absorbing particles (organic refractory) as well as with low absorbing particles (amorphous silicates) to understand the photopolarimetric behavior (phase function, polarization, and color) of dust aggregates. The effect of aggregate size parameter (X) on the light scattering properties of aggregates (BA and BAM2) having different porosities is explored in this study. We find that the positive polarization maximum (P max), the amplitude of the negative polarization (P min) and phase function at the exact backscattering direction (S 11 (180 •)) are correlated with the porosity of aggregates. Compact aggregates show deeper negative polarization as compared to porous aggregates when the characteristic radius (R) of the aggregates are considered to be the same. Further lower porosity aggregates show higher S 11 (180 •) and vice versa. When P is increased in a range from 0.64 to 0.98, both S 11 (180 •) and P min decrease linearly, whereas P max increases linearly. We also find that the porosity of the aggregates plays a crucial role in determining the polarimetric color for high absorbing organic refractories. The compact clusters (BAM1 and BAM2) show the negative polarimetric color whereas
Icarus
In this work, we study the light scattering properties of dust aggregates (0.7µm R c 2.0µm) havin... more In this work, we study the light scattering properties of dust aggregates (0.7µm R c 2.0µm) having a wide range of porosity (P = 0.59 to 0.98). The simulations are executed using the Superposition Tmatrix code with BCCA, BA, BAM1 and BAM2 clusters of varying porosity. We investigate the nature and dependencies of the different scattering parameters on porosity, size and composition of the aggregated particles for wavelengths 0.45 µm and 0.65 µm. We find that the scattering parameters are strongly correlated with the porosity of the aggregated structures. Our results indicate that, when the porosity of the aggregates decreases, keeping characteristic radius of the aggregates (R c) same for all structures, there is an enhancement in the negative polarization branch (NPB) which is accompanied by a substantial increase in the anisotropies present in the material. Also at the exact backscattering region, the anisotropies are found to be linearly correlated with the porosity of the aggregated structure. The computational study reveals that, for low absorbing materials (k ≤ 0.1), the negative polarization minimum (P min) is strongly correlated with the associated anisotropies. Finally, we put forward a qualitative comparison between our computationally obtained results and some selected data from the Amsterdam Light Scattering Database for both low and high absorbing materials. The experimental results also suggest that an increase in the NPB is always accompanied by an enhancement in the anisotropy at the backscattering region.
Computer Physics Communications
Astrophysics and Space Science, 2017
We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with... more We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with a wide variation of porosity (P) from 0.57 to 0.98. The computations are performed using the Superposition T-matrix code with BAM2 cluster (P ∼ 0.57 − 0.64), BAM1 cluster (P ∼ 0.74), BA or BPCA cluster (P ∼ 0.85 − 0.87) and BCCA cluster (P ∼ 0.98). The simulations are executed at two wavelengths 0.45µm and 0.65µm with highly absorbing particles (organic refractory) as well as with low absorbing particles (amorphous silicates) to understand the pho-topolarimetric behavior (phase function, polarization, and color) of dust aggregates. The effect of aggregate size parameter (X) on the light scattering properties of aggregates (BA and BAM2) having different porosi-ties is explored in this study. We find that the positive polarization maximum (P max), the amplitude of the negative polarization (P min) and phase function at the exact backscattering direction (S 11 (180 •)) are correlated with ...
Research paper, Mar 27, 2015
We report the results obtained from the optical polarimetric study of the light scattered by Come... more We report the results obtained from the optical polarimetric study of the light scattered by Comet C/2013 V1 (Boattini) and Comet 290P/Jager at lower phase angles. The polarimetric observations of two comets have been performed with the 1.04-metre Sampurnanand telescope of ARIES near Nainital in India on 4th \& 5th of December, 2013 and on 24th April, 2014 using R photometric band ($\lambda$ = 630 nm, Delta\DeltaDelta$\lambda$ =120nm). We covered observations in both the pre and post perihelion passage of Comet C/2013 V1 (Boattini) and Comet 290P/Jager at two phase angles sim\simsim 13$^\circ$ and 27$^\circ$. The degree of polarization changes from ($-1.4$$\pm 0.3$)\% to (+2.8$\pm 0.5$)\% for Comet C/2013 V1 (Boattini) and ($-1.6$$\pm 0.5$)\% to (+2.5$\pm 0.5$)\% for Comet 290P/Jager at phase angles sim\simsim 13$^\circ$ and 27$^\circ$ respectively. The change in the physical properties of cometary dust is being well studied from the polarization maps obtained for both the period of observations. It is found that the aperture polarization values are comparable to those of other comets. The variation in the brightness profile of both the comets from the standard canonical nature is also being observed in both the solar and anti-solar direction during this phase which suggests the various physical evolution influencing the cometary comae.
Computer Physics Communications, May 9, 2014
In this paper, we report the development of a java application for Superposition T-matrix code, J... more In this paper, we report the development of a java application for Superposition T-matrix code, JaSTA (Java Superposition T-matrix App), to study the light scattering properties of aggregate structures. It has been developed using Netbeans 7.1.2, which is a java integrated development environment (IDE). The JaSTA uses double precession superposition codes for multi-sphere clusters in random orientation developed by Mackowski & Mischenko (1996). It consists of a Graphical User Interface (GUI) in the front hand and a database of related data in the back hand. Both the interactive GUI and database package directly enables user to model by self-monitoring respective input parameters (namely, wavelength, complex refractive indices, grain size, etc.) to study the related optical properties of cosmic dust (namely, extinction, polarization, etc.) instantly, i.e., with zero computational time. This increases the efficiency of the user. The database of JaSTA is now created for a few sets of input parameters with a plan to create a large database in future. This application also has an option where users can compile and run the scattering code directly for aggregates in GUI environment. The JaSTA aims to provide convenient and quicker data analysis of the optical properties which can be used in different fields like planetary science, atmospheric science, nano science, etc. The current version of this software is developed for Linux and Windows platform to study the light scattering properties of small aggregates which will be extended for larger aggregates using parallel codes in future.
Conference Presentations by Prithish Halder
The theoretical solution to the phenomenon of electromagnetic scattering by small particles was f... more The theoretical solution to the phenomenon of electromagnetic scattering by small particles was first proposed by Gustav Mie. But the analytical solution of the mie scattering is impossible for a human being to achieve due to high matrix orders. With the advent of computers it became possible for us to solve the problem numerically within a fraction of time. As mie theory is restricted to only single spherical particles various techniques were developed to solve the problem for particles which are found in aggregated state. Such a technique is Mackowski and Mischenko's Superposition T-matrix Method (1996). We have developed a java based application called JaSTA (Java Superposition T-Matrix App) to extract the electromagnetic scattering properties of aggregated spherical particles from micron to nano scale using STM code. It was first developed for the interstellar dust particles which are in micron scale and now it has been extended for the aggregated spherical nano particles. JaSTA is very much user friendly compared to other codes as it provides a Graphical User Interface for the user to operate all the calculation based on particular input parameters and it also plots the ouput parameters at the end of calculation. It provides a database management system for the user to store data and reuse when needed without recalculating it.
Title of talk/poster: Study of Light Scattering Properties of Cosmic Dust Aggregates using JaSTA ... more Title of talk/poster: Study of Light Scattering Properties of Cosmic Dust Aggregates using JaSTA
Abstract: Cosmic dust aggregates are particles found in space, which are irregular in shape and has a wide range of diverse porosity. In order to study the light scattering properties of such cosmic dust aggregates a Java application called JaSTA (Java Superposition T-matrix App) is developed by us which is based on Mackowski and Mischenko's superposition t-matrix code. It has a GUI platform which helps the user to calculate various scattering coefficients and also to monitor the code. It also has a graphical interpretation facility with a database in the background.
Teaching Documents by Prithish Halder
ApJS, 2022
The overall understanding of cosmic dust particles is mainly inferred from the different Earth-ba... more The overall understanding of cosmic dust particles is mainly inferred from the different Earth-based measurements of interplanetary dust particles and space missions such as Giotto, Stardust, and Rosetta. The results from these measurements indicate the presence of a wide variety of morphologically significant dust particles. To interpret the light-scattering and thermal emission observations arising due to dust in different regions of space, it is necessary to generate computer-modeled realistic dust structures of various shapes, sizes, porosity, bulk density, aspect ratio, and material inhomogeneity. The present work introduces a Java package called Rough Ellipsoid Structure Tool (REST), which is a collection of multiple algorithms, that aims to craft realistic rough-surface cosmic dust particles from spheres, superellipsoids, and fractal aggregates depending on the measured bulk density and porosity. Initially, spheres having N d dipoles or lattice points are crafted by selecting random material and space seed cells to generate a strongly damaged structure, rough surface, and poked structure. Similarly, REST generates roughsurface superellipsoids and poked structure superellipsoids from initial superellipsoid structures. REST also generates rough fractal aggregates, which are fractal aggregates having rough-surface irregular grains. REST has been applied to create agglomerated debris, agglomerated debris superellipsoids, and mixed-morphology particles. Finally, the light-scattering properties of the respective applied structures are studied to ensure their applicability. REST is a flexible structure tool that shall be useful for generating various types of dust structures that can be applied to studying the physical properties of dust in different regions of space.
Monthly Notices of the Royal Astronomical Society, 2015
We report the results obtained from the optical polarimetric study of the light scattered by come... more We report the results obtained from the optical polarimetric study of the light scattered by comets C/2013 V1 (Boattini) and 290P/Jager at lower phase angles. The polarimetric observations of two comets have been performed with the 1.04-m Sampurnanand telescope of Aryabhatta Research Institute of observational sciencES near Nainital in India on 2013 December 4 and 5, and on 2014 April 24 using R photometric band (λ = 630 nm, λ = 120 nm). We covered observations in both the pre-and post-perihelion passage of comets C/2013 V1 (Boattini) and 290P/Jager at two phase angles ∼ 13 • and 27 •. The degree of polarization changes from (−1.4 ± 0.3) to (+2.8 ± 0.5) per cent for comet C/2013 V1 (Boattini) and (−1.6 ± 0.5) to (+2.5 ± 0.5) per cent for comet 290P/Jager at phase angles ∼13 • and 27 • , respectively. The change in the physical properties of cometary dust is being well studied from the polarization maps obtained for both the period of observations. It is found that the aperture polarization values are comparable to those of other comets. The variation in the brightness profile of both the comets from the standard canonical nature is also being observed in both the solar and antisolar direction during this phase which suggests the various physical evolutions influencing the cometary comae.
Monthly Notices of the Royal Astronomical Society
We investigate the effect of porosity in the Umov effect for the first time using the aggregate d... more We investigate the effect of porosity in the Umov effect for the first time using the aggregate dust model. The Umov effect is an inverse correlation between the reflectivity (or geometric albedo) of an object and the degree of linear polarization of light scattered by it. Three different types of fractal aggregates: ballistic agglomeration (BA), ballistic agglomeration with one migration (BAM1), and ballistic agglomeration with two migrations (BAM2) having porosities 0.87, 0.74, and 0.64, respectively (which have the same characteristic radius ∼1 μm), are considered in our simulations. Using the multisphere T-matrix (mstm) code, maximum positive polarization (Pmax) and geometric albedo (A) are calculated for three different fractal aggregated structures considering amorphous silicate composition. Then Pmax and A are plotted against each other in logarithmic scale that shows a linear inverse correlation and a strong porosity dependence. This study shows that the porosity of the aggr...
Computer Physics Communications
Monthly Notices of the Royal Astronomical Society
In this work, we introduce a comet dust model that incorporates multiple dust morphologies along ... more In this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard polarization-phase curve observed in several comets in the narrow-band continuum. Following the results from Rosetta/midas and COSIMA, we create high porosity hierarchical aggregates (HA) and low porosity (<10 per cent) Solids in the form of agglomerated debris. We also introduce a moderate porosity structure with solids in the core, surrounded by fluffy aggregates called fluffy solids (FS). We study the mixing combinations, (HA and Solids), (HA and FS), and (HA, FS, and Solids) for a range of power-law index n= 2.0 to 3.0 for different sets of mixing percentage of silicate minerals and carbonaceous materials. Polarimetry of the short period comets 1P/Halley and 67P/Churyumov-Gerasimenko match best with the polarization resulting from the combination ...
Astrophysics and Space Science
We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with... more We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with a wide variation of porosity (P) from 0.57 to 0.98. The computations are performed using the Superposition T-matrix code with BAM2 cluster (P ∼ 0.57 − 0.64), BAM1 cluster (P ∼ 0.74), BA or BPCA cluster (P ∼ 0.85 − 0.87) and BCCA cluster (P ∼ 0.98). The simulations are executed at two wavelengths 0.45µm and 0.65µm with highly absorbing particles (organic refractory) as well as with low absorbing particles (amorphous silicates) to understand the photopolarimetric behavior (phase function, polarization, and color) of dust aggregates. The effect of aggregate size parameter (X) on the light scattering properties of aggregates (BA and BAM2) having different porosities is explored in this study. We find that the positive polarization maximum (P max), the amplitude of the negative polarization (P min) and phase function at the exact backscattering direction (S 11 (180 •)) are correlated with the porosity of aggregates. Compact aggregates show deeper negative polarization as compared to porous aggregates when the characteristic radius (R) of the aggregates are considered to be the same. Further lower porosity aggregates show higher S 11 (180 •) and vice versa. When P is increased in a range from 0.64 to 0.98, both S 11 (180 •) and P min decrease linearly, whereas P max increases linearly. We also find that the porosity of the aggregates plays a crucial role in determining the polarimetric color for high absorbing organic refractories. The compact clusters (BAM1 and BAM2) show the negative polarimetric color whereas
Icarus
In this work, we study the light scattering properties of dust aggregates (0.7µm R c 2.0µm) havin... more In this work, we study the light scattering properties of dust aggregates (0.7µm R c 2.0µm) having a wide range of porosity (P = 0.59 to 0.98). The simulations are executed using the Superposition Tmatrix code with BCCA, BA, BAM1 and BAM2 clusters of varying porosity. We investigate the nature and dependencies of the different scattering parameters on porosity, size and composition of the aggregated particles for wavelengths 0.45 µm and 0.65 µm. We find that the scattering parameters are strongly correlated with the porosity of the aggregated structures. Our results indicate that, when the porosity of the aggregates decreases, keeping characteristic radius of the aggregates (R c) same for all structures, there is an enhancement in the negative polarization branch (NPB) which is accompanied by a substantial increase in the anisotropies present in the material. Also at the exact backscattering region, the anisotropies are found to be linearly correlated with the porosity of the aggregated structure. The computational study reveals that, for low absorbing materials (k ≤ 0.1), the negative polarization minimum (P min) is strongly correlated with the associated anisotropies. Finally, we put forward a qualitative comparison between our computationally obtained results and some selected data from the Amsterdam Light Scattering Database for both low and high absorbing materials. The experimental results also suggest that an increase in the NPB is always accompanied by an enhancement in the anisotropy at the backscattering region.
Computer Physics Communications
Astrophysics and Space Science, 2017
We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with... more We study the light scattering properties of moderately large dust aggregates (0.8µm R 2.0µm) with a wide variation of porosity (P) from 0.57 to 0.98. The computations are performed using the Superposition T-matrix code with BAM2 cluster (P ∼ 0.57 − 0.64), BAM1 cluster (P ∼ 0.74), BA or BPCA cluster (P ∼ 0.85 − 0.87) and BCCA cluster (P ∼ 0.98). The simulations are executed at two wavelengths 0.45µm and 0.65µm with highly absorbing particles (organic refractory) as well as with low absorbing particles (amorphous silicates) to understand the pho-topolarimetric behavior (phase function, polarization, and color) of dust aggregates. The effect of aggregate size parameter (X) on the light scattering properties of aggregates (BA and BAM2) having different porosi-ties is explored in this study. We find that the positive polarization maximum (P max), the amplitude of the negative polarization (P min) and phase function at the exact backscattering direction (S 11 (180 •)) are correlated with ...
Research paper, Mar 27, 2015
We report the results obtained from the optical polarimetric study of the light scattered by Come... more We report the results obtained from the optical polarimetric study of the light scattered by Comet C/2013 V1 (Boattini) and Comet 290P/Jager at lower phase angles. The polarimetric observations of two comets have been performed with the 1.04-metre Sampurnanand telescope of ARIES near Nainital in India on 4th \& 5th of December, 2013 and on 24th April, 2014 using R photometric band ($\lambda$ = 630 nm, Delta\DeltaDelta$\lambda$ =120nm). We covered observations in both the pre and post perihelion passage of Comet C/2013 V1 (Boattini) and Comet 290P/Jager at two phase angles sim\simsim 13$^\circ$ and 27$^\circ$. The degree of polarization changes from ($-1.4$$\pm 0.3$)\% to (+2.8$\pm 0.5$)\% for Comet C/2013 V1 (Boattini) and ($-1.6$$\pm 0.5$)\% to (+2.5$\pm 0.5$)\% for Comet 290P/Jager at phase angles sim\simsim 13$^\circ$ and 27$^\circ$ respectively. The change in the physical properties of cometary dust is being well studied from the polarization maps obtained for both the period of observations. It is found that the aperture polarization values are comparable to those of other comets. The variation in the brightness profile of both the comets from the standard canonical nature is also being observed in both the solar and anti-solar direction during this phase which suggests the various physical evolution influencing the cometary comae.
Computer Physics Communications, May 9, 2014
In this paper, we report the development of a java application for Superposition T-matrix code, J... more In this paper, we report the development of a java application for Superposition T-matrix code, JaSTA (Java Superposition T-matrix App), to study the light scattering properties of aggregate structures. It has been developed using Netbeans 7.1.2, which is a java integrated development environment (IDE). The JaSTA uses double precession superposition codes for multi-sphere clusters in random orientation developed by Mackowski & Mischenko (1996). It consists of a Graphical User Interface (GUI) in the front hand and a database of related data in the back hand. Both the interactive GUI and database package directly enables user to model by self-monitoring respective input parameters (namely, wavelength, complex refractive indices, grain size, etc.) to study the related optical properties of cosmic dust (namely, extinction, polarization, etc.) instantly, i.e., with zero computational time. This increases the efficiency of the user. The database of JaSTA is now created for a few sets of input parameters with a plan to create a large database in future. This application also has an option where users can compile and run the scattering code directly for aggregates in GUI environment. The JaSTA aims to provide convenient and quicker data analysis of the optical properties which can be used in different fields like planetary science, atmospheric science, nano science, etc. The current version of this software is developed for Linux and Windows platform to study the light scattering properties of small aggregates which will be extended for larger aggregates using parallel codes in future.
The theoretical solution to the phenomenon of electromagnetic scattering by small particles was f... more The theoretical solution to the phenomenon of electromagnetic scattering by small particles was first proposed by Gustav Mie. But the analytical solution of the mie scattering is impossible for a human being to achieve due to high matrix orders. With the advent of computers it became possible for us to solve the problem numerically within a fraction of time. As mie theory is restricted to only single spherical particles various techniques were developed to solve the problem for particles which are found in aggregated state. Such a technique is Mackowski and Mischenko's Superposition T-matrix Method (1996). We have developed a java based application called JaSTA (Java Superposition T-Matrix App) to extract the electromagnetic scattering properties of aggregated spherical particles from micron to nano scale using STM code. It was first developed for the interstellar dust particles which are in micron scale and now it has been extended for the aggregated spherical nano particles. JaSTA is very much user friendly compared to other codes as it provides a Graphical User Interface for the user to operate all the calculation based on particular input parameters and it also plots the ouput parameters at the end of calculation. It provides a database management system for the user to store data and reuse when needed without recalculating it.
Title of talk/poster: Study of Light Scattering Properties of Cosmic Dust Aggregates using JaSTA ... more Title of talk/poster: Study of Light Scattering Properties of Cosmic Dust Aggregates using JaSTA
Abstract: Cosmic dust aggregates are particles found in space, which are irregular in shape and has a wide range of diverse porosity. In order to study the light scattering properties of such cosmic dust aggregates a Java application called JaSTA (Java Superposition T-matrix App) is developed by us which is based on Mackowski and Mischenko's superposition t-matrix code. It has a GUI platform which helps the user to calculate various scattering coefficients and also to monitor the code. It also has a graphical interpretation facility with a database in the background.