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1. Reduction of the downward energy flux of non-thermal electrons in the solar flare corona due to co-spatial return current losses

Author

Alaoui, Meriem, Holman, Gordon D., and Swisdak, Marc

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

High energy electrons carry much of a solar flare's energy. Therefore, understanding changes in electron beam distributions during their propagation is crucial. A key focus of this paper is how the co-spatial return current reduces the energy flux carried by these accelerated electrons. We systematically compute this reduction for various beam and plasma parameters relevant to solar flares. Our 1D model accounts for collisions between beam and plasma electrons, return current electric-field deceleration, thermalization in a warm target approximation, and runaway electron contributions. The results focus on the classical (Spitzer) regime, offering a valuable benchmark for energy flux reduction and its extent. Return current losses are only negligible for the lowest nonthermal fluxes. We calculate the conditions for return current losses to become significant and estimate the extent of the modification to the beam's energy flux density. We also calculate two additional conditions which occur for higher injected fluxes: (1) where runaway electrons become significant, and (2) where current-driven instabilities might become significant, requiring a model that self-consistently accounts for them. Condition (2) is relaxed and the energy flux losses are reduced in the presence of runaway electrons. All results are dependent on beam and co-spatial plasma parameters. We also examine the importance of the reflection of beam electrons by the return-current electric field. We show that the interpretation of a number of flares needs to be reviewed to account for the effects of return currents., Comment: 22 pages, 11 figures, Submitted to ApJ

Published
2024

2. Next-Generation Comprehensive Data-Driven Models of Solar Eruptive Events

Author

Allred, Joel C., Kerr, Graham S., Alaoui, Meriem, Buitrago-Casas, Juan Camilo, Caspi, Amir, Chen, Bin, Chen, Thomas Y., Glesener, Lindsay, Guidoni, Silvina E., Guo, Fan, Karpen, Judith T., Musset, Sophie, Reeves, Katharine K., and Shih, Albert Y.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

Solar flares and coronal mass ejections are interrelated phenomena that together are known as solar eruptive events. These are the main drivers of space weather and understanding their origins is a primary goal of Heliophysics. In this white paper, we advocate for the allocation of sufficient resources to bring together experts in observations and modeling to construct and test next generation data-driven models of solar eruptive events. We identify the key components necessary for constructing comprehensive end-to-end models including global scale 3D MHD resolving magnetic field evolution and reconnection, small scale simulations of particle acceleration in reconnection exhausts, kinetic scale transport of flare-accelerated particles into the lower solar atmosphere, and the radiative and hydrodynamics responses of the solar atmosphere to flare heating. Using this modeling framework, long-standing questions regarding how solar eruptive events release energy, accelerate particles, and heat plasma can be explored. To address open questions in solar flare physics, we recommend that NASA and NSF provide sufficient research and analysis funds to bring together a large body of researchers and numerical tools to tackle the end-to-end modeling framework that we outline. Current dedicated theory and modeling funding programs are relatively small scale and infrequent; funding agencies must recognize that modern space physics demands the use of both observations and modeling to make rapid progress., Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 9 pages, 4 figures

Published
2023
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3. The Focusing Optics X-ray Solar Imager (FOXSI)

Author

Christe, Steven, Alaoui, Meriem, Allred, Joel, Battaglia, Marina, Baumgartner, Wayne, Buitrago-Casas, Juan Camilo, Caspi, Amir, Chen, Bin, Chen, Thomas, Dennis, Brian, Drake, James, Glesener, Lindsay, Hannah, Iain, Hayes, Laura A., Hudson, Hugh, Inglis, Andrew, Ireland, Jack, Klimchuk, James, Kowalski, Adam, Krucker, Säm, Massone, Anna Maria, Musset, Sophie, Piana, Michele, Ryan, Daniel, Shih, Albert Y., Veronig, Astrid, Vilmer, Nicole, Warmuth, Alexander, and White, Stephen

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

FOXSI is a direct-imaging, hard X-ray (HXR) telescope optimized for solar flare observations. It detects hot plasma and energetic electrons in and near energy release sites in the solar corona via bremsstrahlung emission, measuring both spatial structure and particle energy distributions. It provides two orders of magnitude faster imaging spectroscopy than previously available, probing physically relevant timescales (<1s) never before accessible to address fundamental questions of energy release and efficient particle acceleration that have importance far beyond their solar application (e.g., planetary magnetospheres, flaring stars, accretion disks). FOXSI measures not only the bright chromospheric X-ray emission where electrons lose most of their energy, but also simultaneous emission from electrons as they are accelerated in the corona and propagate along magnetic field lines. FOXSI detects emission from high in the tenuous corona, where previous instruments have been blinded by nearby bright features and will fully characterizes the accelerated electrons and hottest plasmas as they evolve in energy, space, and time to solve the mystery of how impulsive energy release leads to solar eruptions, the primary drivers of space weather at Earth, and how those eruptions are energized and evolve., Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 14 pages, 4 figures, 1 table

Published
2023
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4. Fundamentals of impulsive energy release in the corona

Author

Shih, Albert Y., Glesener, Lindsay, Krucker, Säm, Guidoni, Silvina, Christe, Steven, Reeves, Katharine K., Gburek, Szymon, Caspi, Amir, Alaoui, Meriem, Allred, Joel, Battaglia, Marina, Baumgartner, Wayne, Dennis, Brian, Drake, James, Goetz, Keith, Golub, Leon, Hannah, Iain, Hayes, Laura, Holman, Gordon, Inglis, Andrew, Ireland, Jack, Kerr, Graham, Klimchuk, James, McKenzie, David, Moore, Christopher S., Musset, Sophie, Reep, Jeffrey, Ryan, Daniel, Saint-Hilaire, Pascal, Savage, Sabrina, Seaton, Daniel B., Stęślicki, Marek, and Woods, Thomas N.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

It is essential that there be coordinated and co-optimized observations in X-rays, gamma-rays, and EUV during the peak of solar cycle 26 (~2036) to significantly advance our understanding of impulsive energy release in the corona. The open questions include: What are the physical origins of space-weather events? How are particles accelerated at the Sun? How is impulsively released energy transported throughout the solar atmosphere? How is the solar corona heated? Many of the processes involved in triggering, driving, and sustaining solar eruptive events -- including magnetic reconnection, particle acceleration, plasma heating, and energy transport in magnetized plasmas -- also play important roles in phenomena throughout the Universe. This set of observations can be achieved through a single flagship mission or, with foreplanning, through a combination of major missions (e.g., the previously proposed FIERCE mission concept)., Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 5 pages, 1 figure

Published
2023
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5. The need for focused, hard X-ray investigations of the Sun

Author

Glesener, Lindsay, Shih, Albert Y., Caspi, Amir, Milligan, Ryan, Hudson, Hugh, Oka, Mitsuo, Buitrago-Casas, Juan Camilo, Guo, Fan, Ryan, Dan, Kontar, Eduard, Veronig, Astrid, Hayes, Laura A., Inglis, Andrew, Golub, Leon, Vilmer, Nicole, Gary, Dale, Reid, Hamish, Hannah, Iain, Kerr, Graham S., Reeves, Katharine K., Allred, Joel, Guidoni, Silvina, Yu, Sijie, Christe, Steven, Musset, Sophie, Dennis, Brian, Oliveros, Juan Carlos Martínez, Athiray, P. S., Vievering, Juliana, White, Stephen, Winebarger, Amy, Drake, James, Jeffrey, Natasha, Antiochos, Spiro, Duncan, Jessie, Zhang, Yixian, Alaoui, Meriem, Simões, Paulo J. A., Battaglia, Marina, Setterberg, William, Masek, Reed, Chen, Thomas Y., Peterson, Marianne, Krucker, Säm, Temmer, Manuela, Saint-Hilaire, Pascal, Petrosian, Vahe, Knuth, Trevor, and Moore, Christopher S.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

Understanding the nature of energetic particles in the solar atmosphere is one of the most important outstanding problems in heliophysics. Flare-accelerated particles compose a huge fraction of the flare energy budget; they have large influences on how events develop; they are an important source of high-energy particles found in the heliosphere; and they are the single most important corollary to other areas of high-energy astrophysics. Despite the importance of this area of study, this topic has in the past decade received only a small fraction of the resources necessary for a full investigation. For example, NASA has selected no new Explorer-class instrument in the past two decades that is capable of examining this topic. The advances that are currently being made in understanding flare-accelerated electrons are largely undertaken with data from EOVSA (NSF), STIX (ESA), and NuSTAR (NASA Astrophysics). This is despite the inclusion in the previous Heliophysics decadal survey of the FOXSI concept as part of the SEE2020 mission, and also despite NASA's having invested heavily in readying the technology for such an instrument via four flights of the FOXSI sounding rocket experiment. Due to that investment, the instrumentation stands ready to implement a hard X-ray mission to investigate flare-accelerated electrons. This white paper describes the scientific motivation for why this venture should be undertaken soon., Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 15 pages, 5 figures

Published
2023
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7. Role of Suprathermal Runaway Electrons Returning to the Acceleration Region in Solar Flares

Author

Alaoui, Meriem, Holman, Gordon D., Allred, Joel C., and Eufrasio, Rafael T.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Plasma Physics, Physics - Space Physics
Abstract

During solar flares, a large flux of energetic electrons propagate from the tops of reconnecting magnetic flux tubes toward the lower atmosphere. Over the course of the electrons' transport, a co-spatial counter-streaming return current is induced, thereby balancing the current density. In response to the return current electric field, a fraction of the ambient electrons will be accelerated into the runaway regime. However, models describing the accelerated electron beam/return-current system have generally failed to take these suprathermal runaway electrons into account self-consistently. We develop a model in which an accelerated electron beam drives a steady-state, sub-Dreicer co-spatial return-current electric field, which locally balances the direct beam current and freely accelerates a fraction of background (return-current) electrons. The model is self-consistent, i.e., the electric field induced by the co-evolution of the direct beam and the runaway current is considered. We find that (1) the return current electric field can return a significant number of suprathermal electrons to the acceleration region, where they can be further accelerated to higher energies, runaway electrons can be a few tens of percent of the return current flux returning to the nonthermal beam's acceleration region, (2) the energy gain of the suprathermal electrons can be up to $10-35$\,keV, (3) the heating rate in the corona can be reduced by an order of magnitude in comparison to models which neglect the runaway component. The results depend on the injected beam flux density, the temperature and density of the background plasma., Comment: 19 pages, 10 figures, submitted to ApJ

Published
2021
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8. Solar Flare Energy Partitioning and Transport -- the Gradual Phase (a Heliophysics 2050 White Paper)

Author

Kerr, Graham S., Alaoui, Meriem, Allred, Joel C., Bian, Nicholas H., Dennis, Brian R., Emslie, A. Gordon, Fletcher, Lyndsay, Guidoni, Silvina, Hayes, Laura A., Holman, Gordon D., Hudson, Hugh S., Karpen, Judith T., Kowalski, Adam F., Milligan, Ryan O., Polito, Vanessa, Qiu, Jiong, and Ryan, Daniel F.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Solar flares are a fundamental component of solar eruptive events (SEEs; along with solar energetic particles, SEPs, and coronal mass ejections, CMEs). Flares are the first component of the SEE to impact our atmosphere, which can set the stage for the arrival of the associated SEPs and CME. Magnetic reconnection drives SEEs by restructuring the solar coronal magnetic field, liberating a tremendous amount of energy which is partitioned into various physical manifestations: particle acceleration, mass and magnetic-field eruption, atmospheric heating, and the subsequent emission of radiation as solar flares. To explain and ultimately predict these geoeffective events, the heliophysics community requires a comprehensive understanding of the processes that transform and distribute stored magnetic energy into other forms, including the broadband radiative enhancement that characterises flares. This white paper, submitted to the Heliophysics 2050 Workshop, discusses the flare gradual phase part of SEEs, setting out the questions that need addressing via a combination of theoretical, modelling, and observational research. In short, the flare gradual phase persists much longer than predicted so, by 2050, we must identify the characteristics of the significant energy deposition sustaining the gradual phase, and address the fundamental processes of turbulence and non-local heat flux., Comment: White paper submitted to the Heliophysics 2050 Workshop

Published
2020

9. Solar Flare Energy Partitioning and Transport -- the Impulsive Phase (a Heliophysics 2050 White Paper)

Author

Kerr, Graham S., Alaoui, Meriem, Allred, Joel C., Bian, Nicholas H., Dennis, Brian R., Emslie, A. Gordon, Fletcher, Lyndsay, Guidoni, Silvina, Hayes, Laura A., Holman, Gordon D., Hudson, Hugh S., Karpen, Judith T., Kowalski, Adam F., Milligan, Ryan O., Polito, Vanessa, Qiu, Jiong, and Ryan, Daniel F.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Physics - Space Physics
Abstract

Solar flares are a fundamental component of solar eruptive events (SEEs; along with solar energetic particles, SEPs, and coronal mass ejections, CMEs). Flares are the first component of the SEE to impact our atmosphere, which can set the stage for the arrival of the associated SEPs and CME. Magnetic reconnection drives SEEs by restructuring the solar coronal magnetic field, liberating a tremendous amount of energy which is partitioned into various physical manifestations: particle acceleration, mass and magnetic-field eruption, atmospheric heating, and the subsequent emission of radiation as solar flares. To explain and ultimately predict these geoeffective events, the heliophysics community requires a comprehensive understanding of the processes that transform and distribute stored magnetic energy into other forms, including the broadband radiative enhancement that characterises flares. This white paper, submitted to the Heliophysics 2050 Workshop, discusses the flare impulsive phase part of SEEs, setting out the questions that need addressing via a combination of theoretical, modelling, and observational research. In short, by 2050 we must determine the mechanisms of particle acceleration and propagation, and must push beyond the paradigm of energy transport via nonthermal electron beams, to also account for accelerated protons & ions and downward directed Alfven waves., Comment: White paper submitted to the Heliophysics 2050 Workshop

Published
2020

10. Modeling the Transport of Nonthermal Particles in Flares Using Fokker-Planck Kinetic Theory

Author

Allred, Joel C., Alaoui, Meriem, Kowalski, Adam F., and Kerr, Graham S.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We describe a new approach for modeling the transport of high energy particles accelerated during flares from the acceleration region in the solar corona until their eventual thermalization in the flare footpoint. Our technique numerically solves the Fokker-Planck equation and includes forces corresponding to Coulomb collisions in a flux loop with nonuniform ionization, synchrotron emission reaction, magnetic mirroring and a return current electric field. Our solution to the Fokker-Planck equation includes second-order pitch angle and momentum diffusion. It is applicable to particles of arbitrary mass and charge. By tracking the collisions, we predict the bremsstrahlung produced as these particles interact with the ambient stellar atmosphere. This can be compared directly with observations and used to constrain the accelerated particle energy distribution. We have named our numerical code FP and have distributed it for general use. We demonstrate its effectiveness in several test cases., Comment: Accepted for publication in the Astrophysical Journal, 19 pages, 7 figures

Published
2020
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11. Substrate Type Effects on Vegetative Growth and Development of 'Argania spinosa L. skeel' Tree Seedlings

Author

Farhoune, Hassania, Alaoui, Meriem Mdarhri, Cherkaoui, Souad, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Balas, Valentina E., editor, and Ezziyyani, Mostafa, editor

Published
2022
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12. Understanding breaks in solar flares x-ray spectra: Evaluation of a co-spatial return-current model

Author

Alaoui, Meriem and Holman, Gordon

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

Hard x-ray spectral breaks are explained in terms of a 1D model with a co-spatial return current. We study 19 flares observed by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) with strong spectral breaks at energies around a few deka-keV, that cannot be explained by isotropic albedo or non-uniform ionization alone. We identify these breaks at the HXR peak time, but we obtain 8 s-cadence spectra of the entire impulsive phase. Electrons with an initially power-law distribution and a sharp low-energy cutoff lose energy through return-current losses until they reach the thick target, where they lose their remaining energy through collisions. Our main results are: (1) The return-current collisional thick-target model (RCCTTM) provides acceptable fits for spectra with strong breaks. (2) Limits on the plasma resistivity are derived from the fitted potential drop and deduced electron-beam flux density, assuming the return-current is a drift current in the ambient plasma. These resistivities are typically 2-3 orders of magnitude higher than the Spitzer resistivity at the fitted temperature, and provide a test for the adequacy of classical resistivity and the stability of the return current. (3) Using the upper limit of the low-energy cutoff, the return current is always stable to the generation of ion acoustic and electrostatic ion cyclotron instabilities when the electron temperature is lower than 9 times the ion temperature. (4) In most cases the return current is most likely primarily carried by runaway electrons from the tail of the thermal distribution rather than the bulk drifting thermal electrons. For these cases, anomalous resistivity is not required., Comment: 47 pages, 14 figures

Published
2017
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13. Reduction of the Downward Energy Flux of Nonthermal Electrons in the Solar Flare Corona due to Cospatial Return-current Losses.

Author

Alaoui, Meriem, Holman, Gordon D., and Swisdak, M.

Subjects
*SUN, *ELECTRON distribution, *SOLAR heating, *SOLAR corona, *ELECTRON beams
Abstract

High-energy electrons carry much of a solar flare's energy. Therefore, understanding changes in electron beam distributions during their propagation is crucial. A key focus of this paper is how the cospatial return current reduces the energy flux carried by these accelerated electrons. We systematically compute this reduction for various beam and plasma parameters relevant to solar flares. Our 1D model accounts for collisions between beam and plasma electrons, return-current electric-field deceleration, thermalization in a warm target approximation, and runaway electron contributions. The results focus on the classical (Spitzer) regime, offering a valuable benchmark for energy flux reduction and its extent. Return-current losses are only negligible for the lowest nonthermal fluxes. We calculate the conditions for return-current losses to become significant and estimate the extent of the modification to the beam's energy flux density. We also calculate two additional conditions that occur for higher injected fluxes: (1) where runaway electrons become significant, and (2) where current-driven instabilities might become significant, requiring a model that self-consistently accounts for them. Condition 2 is relaxed and the energy flux losses are reduced in the presence of runaway electrons. All results are dependent on beam and cospatial plasma parameters. We also examine the importance of the reflection of beam electrons by the return-current electric field. We show that the interpretation of a number of flares needs to be reviewed to account for the effects of return currents. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Assessing the Evolution of Stability and Maturity in Co-Composting Sheep Manure with Green Waste Using Physico-Chemical and Biological Properties and Statistical Analyses: A Case Study of Botanique Garden in Rabat, Morocco.

Author

Oueld Lhaj, Majda, Moussadek, Rachid, Mouhir, Latifa, Mdarhri Alaoui, Meriem, Sanad, Hatim, Iben Halima, Oumaima, and Zouahri, Abdelmjid

Subjects
SUSTAINABLE development, ORGANIC waste recycling, SUSTAINABILITY, AGRICULTURE, CIRCULAR economy, COMPOSTING, ODORS
Abstract

Organic waste utilization stands as a pivotal approach to ecological and economic sustainability. This study aimed to assess the stability, maturity, and evolution of co-composts comprising various blends of green waste (GW) and sheep manure (SM). Employing a diverse array of physico-chemical and biological parameters, we investigated the co-composting process over 120 days. Three types of garden waste (mixture of green waste (MGW), fallen leaves (FL), and grass cutting (GC)) were utilized. The results revealed significant compost transformation, evident by odor and insect absence and a shift to dark brown coloration, indicating maturation. The compost C2, derived from FL, exhibited superior soil amendment potential. Significantly, it exhibited a pH level of 6.80, an EC of 2.45 mS/cm, and an OM content of 55%, along with a C/N ratio of 16.15. Analysis of the macronutrients revealed values of 1.98% for TN, 3.22% for TP, and 0.61% for K. Crucially, the compost showed no phytotoxic effects and boasted a high GI of 94.20% and a low respiration rate of 4.02 mg/50 g, indicating its stability and appropriateness for agricultural application. Our findings underscore compost's potential as an eco-friendly soil amendment, offering valuable insights for sustainable agricultural management and supporting the circular economy. [ABSTRACT FROM AUTHOR]

Published
2024
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17. Next-Generation Comprehensive Data-Driven Models of Solar Eruptive Events

Author

Allred, Joel C., primary, Kerr, Graham S., additional, Alaoui, Meriem, additional, Buitrago-Casas, Juan Camilo, additional, Caspi, Amir, additional, Chen, Bin, additional, Chen, Thomas Y., additional, Glesener, Lindsay, additional, Guidoni, Silvina E., additional, Guo, Fan, additional, Karpen, Judith, additional, Musset, Sophie, additional, Reeves, Katharine K., additional, and Shih, Albert Y., additional

Published
2023
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18. COMPLETE: a flagship mission for complete understanding of 3D coronal magnetic energy release

Author

Caspi, Amir, primary, Casini, Roberto, additional, Downs, Cooper, additional, Gibson, Sarah, additional, Gilbert, Holly, additional, Glesener, Lindsay, additional, Guidoni, Silvina, additional, Hughes, J. Marcus, additional, McKenzie, David, additional, Plowman, Joseph, additional, Seaton, Daniel, additional, Reeves, Katharine, additional, Saint-Hilaire, Pascal, additional, Shih, Albert Y., additional, West, Matthew, additional, Alaoui, Meriem, additional, Alexander, David, additional, Allred, Joel C., additional, Ashfield, William, additional, Bradshaw, Stephen J., additional, Bröse, Malte, additional, Buitrago-Casas, Juan Camilo, additional, Chamberlin, Phillip, additional, Chandra, Ramesh, additional, Che, Haihong, additional, Chen, Thomas Y., additional, Chen, Bin, additional, Cheng, Xin, additional, Christe, Steven, additional, Dahlin, Joel, additional, Nolfo, Georgia de, additional, Dickson, Ewan C. M., additional, Dudík, Jaroslav, additional, Emslie, Gordon, additional, Erdelyi, Robertus, additional, Gallagher, Peter T., additional, Gan, Weiqun, additional, Gary, Dale, additional, Guo, Fan, additional, Hayes, Laura A., additional, Hudson, Hugh, additional, Ji, Hantao, additional, Jones, Andrew R., additional, Kerr, Graham S., additional, Keshav, Aggarwal, additional, Knuth, Trevor, additional, Kooi, Jason, additional, Kumari, Anshu, additional, Li, Ying, additional, Limousin, Olivier, additional, Longo, Francesco, additional, Maharana, Anwesha, additional, Mandrini, Cristina H., additional, Oliveros, Juan Carlos Martinez, additional, Massone, Anna Maria, additional, McAteer, R. T. James, additional, McConnell, Mark, additional, McTiernan, James, additional, Meuris, Aline, additional, Mitchell, J. Grant, additional, Motorina, Galina, additional, Mrozek, Tomasz, additional, Musset, Sophie, additional, Narukage, Noriyuki, additional, Nayak, Sushree S., additional, Newmark, Jeffrey, additional, Nitta, Nariaki, additional, Panesar, Navdeep, additional, Pariat, Etienne, additional, Piana, Michele, additional, Qiu, Jiong, additional, Raouafi, Nour E., additional, Reale, Fabio, additional, Rozelot, Jean Pierre, additional, Samaiyah, Farid, additional, Sarkar, Ranadeep, additional, Shaik, Shaheda Begum, additional, Skokic, Ivica, additional, Stores, Morgan, additional, Struminsky, Alexei, additional, Su, Yang, additional, Takahashi, Tadayuki, additional, Tiwari, Sanjiv, additional, Tsiklauri, David, additional, Vievering, Juliana T., additional, Warmuth, Alexander, additional, White, Stephen, additional, Zhang, Jie, additional, and Zimovets, Ivan V., additional

Published
2023
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19. High-Energy Aspects of the Solar-Stellar Connection

Author

Vievering, Juliana T., primary, Glesener, Lindsay, additional, Caspi, Amir, additional, Allred, Joel, additional, Chen, Thomas Y., additional, Lustig-Yaeger, Jacob, additional, Kerr, Graham S., additional, Inglis, Andrew, additional, Alaoui, Meriem, additional, and Mayorga, L. C., additional

Published
2023
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20. The Focusing Optics X-ray Solar Imager (FOXSI)

Author

Christe, Steven, primary, Alaoui, Meriem, additional, Allred, Joel, additional, Battaglia, Marina, additional, Baumgartner, Wayne, additional, Buitrago-Casas, J. C., additional, Chen, Bin, additional, Chen, Thomas, additional, Dennis, Brian, additional, Drake, James, additional, Glesener, Lindsay, additional, Hannah, Iain, additional, Hudson, Hugh, additional, Inglis, Andrew, additional, Ireland, Jack, additional, Klimchuk, James, additional, Kowalski, Adam, additional, Krucker, Säm, additional, Massone, Anna Maria, additional, Musset, Sophie, additional, Piana, Michele, additional, Ryan, Daniel, additional, Shih, Albert, additional, Veronig, Astrid, additional, Vilmer, Nicole, additional, Warmuth, Alexander, additional, White, Stephen, additional, Caspi, Amir, additional, and Hayes, Laura A., additional

Published
2023
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21. Requirements for Progress in Understanding Solar Flare Energy Transport: The Impulsive Phase

Author

Kerr, Graham S., primary, Alaoui, Meriem, additional, Allred, Joel C., additional, Ashfield, William, additional, Chen, Thomas, additional, Dennis, Brian, additional, Emslie, A. Gordon, additional, Fletcher, Lyndsay, additional, French, Ryan, additional, Guidoni, Silvina E., additional, Guo, Fan, additional, Hayes, Laura A., additional, Hudson, Hugh H., additional, Inglis, Andrew R., additional, Karpen, Judith T., additional, Kowalski, Adam F., additional, Milligan, Ryan O., additional, McLaughlin, Shaun, additional, Monson, Aaron, additional, Polito, Vanessa, additional, Qiu, Jiong, additional, Ryan, Daniel F., additional, and Shih, Albert Y., additional

Published
2023
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22. Requirements for Progress in Understanding Solar Flare Energy Transport: The Gradual Phase

Author

Kerr, Graham S., primary, Alaoui, Meriem, additional, Allred, Joel C., additional, Ashfield, William, additional, Chen, Thomas, additional, Dennis, Brian, additional, Emslie, A. Gordon, additional, Fletcher, Lyndsay, additional, French, Ryan, additional, Guidoni, Silvina E., additional, Guo, Fan, additional, Hayes, Laura A., additional, Hudson, Hugh H., additional, Inglis, Andrew R., additional, Karpen, Judith T., additional, Klimchuk, James A., additional, Kowalski, Adam F., additional, Milligan, Ryan O., additional, McLaughlin, Shaun, additional, Monson, Aaron, additional, Polito, Vanessa, additional, Qiu, Jiong, additional, Ryan, Daniel F., additional, and Shih, Albert Y., additional

Published
2023
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23. Improving Multi-Dimensional Data Formats, Access, and Assimilation Tools for the Twenty-First Century

Author

Seaton, Daniel, primary, Caspi, Amir, additional, Casini, Roberto, additional, Downs, Cooper, additional, Gibson, Sarah, additional, Gilbert, Holly, additional, Glesener, Lindsay, additional, Guidoni, Silvina, additional, Hughes, J. Marcus, additional, McKenzie, David, additional, Plowman, Joseph, additional, Reeves, Katharine, additional, Saint-Hilaire, Pascal, additional, Shih, Albert Y., additional, West, Matthew, additional, Alaoui, Meriem, additional, Alzate, Nathalia, additional, Ashfield, William, additional, Bradshaw, Stephen J., additional, Buitrago-Casas, Juan Camilo, additional, Che, Haiong, additional, Chen, Thomas Y., additional, Christe, Steven, additional, Erdelyi, Robertus, additional, Farid, Samaiyah, additional, Gallagher, Peter T., additional, Gary, Dale, additional, Gilly, Chris, additional, Guo, Fan, additional, Hayes, Laura A., additional, Hudson, Hugh, additional, Ji, Hantao, additional, Jones, Andrew R., additional, Keshav, Aggarwal, additional, Kirk, Michael S., additional, Knuth, Trevor, additional, Kobelski, Adam, additional, Kooi, Jason, additional, Kumari, Anshu, additional, Li, Ying, additional, Li, Jing, additional, Lowder, Chris, additional, Mandrini, Cristina H., additional, Oliveros, Juan Carlos Martinez, additional, Mason, James Paul, additional, Mason, E. I., additional, Massone, Anna Maria, additional, McAteer, R. T. James, additional, McTiernan, James, additional, Motorina, Galina, additional, Nayak, Sushree S., additional, Nitta, Nariaki, additional, Panesar, Navdeep, additional, Pariat, Etienne, additional, Piana, Michele, additional, Reale, Fabio, additional, Reardon, Kevin, additional, Rivera, Yeimy, additional, Sarkar, Ranadeep, additional, Shaikh, Zubair, additional, Stores, Morgan, additional, Tiwari, Sanjiv, additional, Warmuth, Alexander, additional, and White, Stephen, additional

Published
2023
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24. The need for focused, hard X-ray investigations of the Sun

Author

Glesener, Lindsay, primary, Shih, Albert Y., additional, Caspi, Amir, additional, Milligan, Ryan, additional, Hudson, Hugh, additional, Oka, Mitsuo, additional, Buitrago-Casas, Juan Camilo, additional, Guo, Fan, additional, Ryan, Dan, additional, Kontar, Eduard, additional, Veronig, Astrid, additional, Hayes, Laura A., additional, Inglis, Andrew, additional, Golub, Leon, additional, Vilmer, Nicole, additional, Gary, Dale, additional, Reid, Hamish, additional, Hannah, Iain, additional, Kerr, Graham S., additional, Reeves, Katharine K., additional, Allred, Joel, additional, Guidoni, Silvina, additional, Yu, Sijie, additional, Christe, Steven, additional, Musset, Sophie, additional, Dennis, Brian, additional, Oliveros, Juan Carlos Martinez, additional, Athiray, P. S., additional, Vievering, Juliana, additional, White, Stephen, additional, Winebarger, Amy, additional, Drake, James, additional, Jeffrey, Natasha, additional, Antiochos, Spiro, additional, Duncan, Jessie, additional, Zhang, Yixian, additional, Alaoui, Meriem, additional, Simões, Paulo J. A., additional, Battaglia, Marina, additional, Setterberg, William, additional, Masek, Reed, additional, Chen, Thomas Y., additional, Peterson, Marianne, additional, Krucker, Säm, additional, Temmer, Manuela, additional, Saint-Hilaire, Pascal, additional, Petrosian, Vahe, additional, Knuth, Trevor, additional, and Moore, Christopher, additional

Published
2023
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25. Frequency Agile Solar Radiotelescope

Author

Gary, Dale, primary, Chen, Bin, additional, White, Stephen, additional, Bastian, Timothy, additional, Saint-Hilaire, Pascal, additional, Drake, James, additional, Glesener, Lindsay, additional, Yu, Sijie, additional, Mondal, Surajit, additional, Fleishman, Gregory, additional, Vourlidas, Angelos, additional, Bale, Stuart, additional, Chhabra, Sherry, additional, Cohen, Christina, additional, DeForest, Craig, additional, Oliveros, Juan Carlos Martinez, additional, Ji, Hantao, additional, Buitrago-Casas, Juan Camilo, additional, Habbal, Shadia, additional, Lanzerotti, Louis J., additional, Shaik, Shaheda Begum, additional, Molnar, Momchil, additional, Nita, Gelu, additional, Emslie, Gordon, additional, Reardon, Kevin, additional, Guo, Fan, additional, Oka, Mitsuo, additional, Nitta, Nariaki, additional, Sun, Xudong, additional, Landi, Enrico, additional, Ofman, Leon, additional, Lee, Jeongwoo, additional, Hudson, Hugh, additional, Veronig, Astrid, additional, Qiu, Jiong, additional, Leka, KD, additional, Harvey, John, additional, Chen, Thomas Y., additional, Antiochos, Spiro, additional, Moore, Ron, additional, West, Matthew, additional, Dahlin, Joel, additional, Kosovichev, Alexander, additional, Knipp, Delores, additional, Raouafi, Nour, additional, Li, Xiaocan, additional, Schad, Thomas, additional, Kontar, Eduard, additional, Hayes, Laura, additional, Shen, Chengcai, additional, Castro, Guillermo Giménez de, additional, Hannah, Iain, additional, Solanki, Sami K., additional, Arnold, Harry, additional, Yurchyshyn, Vasyl, additional, Cheung, Mark, additional, Pillet, Valentin Martinez, additional, Tarr, Lucas, additional, Karpen, Judy, additional, Caspi, Amir, additional, Shih, Albert Y., additional, Anan, Tetsu, additional, Battaglia, Andrea Francesco, additional, Lin, Haosheng, additional, Alaoui, Meriem, additional, Reeves, Katharine K., additional, Guidoni, Silvina, additional, Klimchuk, James, additional, Kooi, Jason, additional, Kazachenko, Maria, additional, Beltran, Samuel Tun, additional, McTiernan, James, additional, Kuroda, Natsuha, additional, Schonfeld, Samuel, additional, Kahler, Stephen, additional, Downs, Cooper, additional, Cauzzi, Gianna, additional, Musset, Sophie, additional, Gilly, Chris R., additional, Asai, Ayumi, additional, Welsch, Brian, additional, Shimojo, Masumi, additional, Fan, Yuhong, additional, Masuda, Satoshi, additional, O’Donnell, Brian, additional, and Kumar, Pankaj, additional

Published
2023
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26. Fundamentals of impulsive energy release in the corona

Author

Shih, Albert Y., primary, Glesener, Lindsay, additional, Krucker, Säm, additional, Guidoni, Silvina, additional, Christe, Steven, additional, Reeves, Katharine K., additional, Gburek, Szymon, additional, Caspi, Amir, additional, Alaoui, Meriem, additional, Allred, Joel C., additional, Battaglia, Marina, additional, Baumgartner, Wayne, additional, Dennis, Brian R., additional, Drake, James, additional, Goetz, Keith, additional, Golub, Leon, additional, Hannah, Iain, additional, Hayes, Laura A., additional, Holman, Gordon, additional, Inglis, Andrew, additional, Ireland, Jack, additional, Kerr, Graham S., additional, Klimchuk, James, additional, McKenzie, David E., additional, Moore, Christopher, additional, Musset, Sophie, additional, Reep, Jeffrey, additional, Ryan, Daniel, additional, Saint-Hilaire, Pascal, additional, Savage, Sabrina, additional, Seaton, Daniel B., additional, Stęślicki, Marek, additional, and Woods, Thomas, additional

Published
2023
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27. Magnetic Energy Powers the Corona: How We Can Understand its 3D Storage & Release

Author

Caspi, Amir, primary, Seaton, Daniel, additional, Casini, Roberto, additional, Downs, Cooper, additional, Gibson, Sarah, additional, Gilbert, Holly, additional, Glesener, Lindsay, additional, Guidoni, Silvina, additional, Hughes, J. Marcus, additional, McKenzie, David, additional, Plowman, Joseph, additional, Reeves, Katharine, additional, Saint-Hilaire, Pascal, additional, Shih, Albert Y., additional, West, Matthew, additional, Alaoui, Meriem, additional, Alexander, David, additional, Allred, Joel C., additional, Antiochos, Spiro, additional, Ashfield, William, additional, Ballai, Istvan, additional, Barata, Teresa, additional, Barta, Miroslav, additional, Benz, Arnold O., additional, Berlicki, Arkadiusz, additional, Bradshaw, Stephen J., additional, Bröse, Malte, additional, Buitrago-Casas, Juan Camilo, additional, Cassak, Paul, additional, Chamberlin, Phillip, additional, Che, Haihong, additional, Chen, Thomas Y., additional, Chen, Bin, additional, Cheng, Xin, additional, Christe, Steven, additional, Comisso, Luca, additional, Dahlin, Joel, additional, Nolfo, Georgia de, additional, Dennis, Brian, additional, Dickson, Ewan C. M., additional, Drake, James, additional, Dudík, Jaroslav, additional, Dzifcakova, Elena, additional, Emslie, Gordon, additional, Erdelyi, Robertus, additional, Farid, Samaiyah, additional, Fleishman, Gregory, additional, French, Ryan, additional, Gallagher, Peter T., additional, Gan, Weiqun, additional, Gary, Dale, additional, Guo, Fan, additional, Hayes, Laura A., additional, Hudson, Hugh, additional, Ji, Hantao, additional, Jones, Andrew R., additional, Kansabanik, Devojyoti, additional, Kawate, Tomoko, additional, Kerr, Graham S., additional, Keshav, Aggarwal, additional, Knuth, Trevor, additional, Kobelski, Adam, additional, Kooi, Jason, additional, Kumari, Anshu, additional, Lee, Jeongwoo, additional, Li, Ying, additional, Longo, Francesco, additional, Maharana, Anwesha, additional, Mandrini, Cristina H., additional, Oliveros, Juan Carlos Martinez, additional, Mason, James Paul, additional, Mason, E. I., additional, Massone, Anna Maria, additional, McAteer, R. T. James, additional, McConnell, Mark, additional, McTiernan, James, additional, Mitchell, J. Grant, additional, Mohan, Atul, additional, Motorina, Galina, additional, Mrozek, Tomasz, additional, Musset, Sophie, additional, Narukage, Noriyuki, additional, Nayak, Sushree S., additional, Nitta, Nariaki, additional, Panesar, Navdeep, additional, Pariat, Etienne, additional, Piana, Michele, additional, Pohjolainen, Silja, additional, Qiu, Jiong, additional, Reale, Fabio, additional, Rivera, Yeimy, additional, Rozelot, Jean Pierre, additional, Sarkar, Ranadeep, additional, Setterberg, William, additional, Shaik, Shaheda Begum, additional, Shaikh, Zubair, additional, Sharma, Rohit, additional, Skokic, Ivica, additional, Stores, Morgan, additional, Struminsky, Alexei, additional, Sylwester, Janusz, additional, Takahashi, Tadayuki, additional, Tiwari, Sanjiv, additional, Tsiklauri, David, additional, Vievering, Juliana T., additional, Warmuth, Alexander, additional, White, Stephen, additional, and Zimovets, Ivan V., additional

Published
2023
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28. EMPLOYER BRANDING AS A TOOL FOR EMPLOYEE LOYALTY: THE CASE OF MOROCCAN COMPANIES LISTED ON CASABLANCA STOCK EXCHANGE: Received: 24th April 2023; Revised: 27th July 2023, 11th August 2023; Accepted: 15th August 2023

Author

OUACHI, Soukayna, ALAOUI, Meriem, OUACHI, Soukayna, and ALAOUI, Meriem

Abstract

To attract qualified profiles, known as talents, and to retain them, many enterprises are actively leveraging on employer branding. The objective of this research is to shed light on the role played by the concept of employer branding, defined as the set of brand image assets with respect to employees and their impact on human resources loyalty. Our hypothetico-deductive research method will be completed by conducting an empirical study based on a series of semi-structured interviews with 10 large companies listed on Casablanca stock exchange market. We suggest a model to articulate the employer brand around three key dimensions: low propensity to seek a new job, affective engagement and task performance. The collected and analyzed feedback led us to a clear and obvious conclusion. The intention to leave the company, the affective commitment as well as the performance in the task are directly impacted by the attributes of the employer brand. Therefore, organizational loyalty is influenced by the employer brand. The latter is a powerful loyalty tool that allows the company to retain talent. Further research should be conducted to explore the potential of employer branding as a powerful tool for talent retention.

Published
2023

31. Radiation resistance of high frequency ultrasonic devices for distance measurement in the RHF

Author

Alaoui Meriem Chrifi, Le Clézio, Emmanuel, Despaux Gilles, and Calzavara Yoann

Subjects
Physics, QC1-999
Abstract

The fuel element plates of research reactors are subjected to swelling phenomena. These structure modifications impact an initial inter-plate distance of 1.8 mm. An ultrasonic device has been developed to investigate this parameter. With a 1 mm thickness, it relies on two transducers linked to an electronic system. The feasibility of the distance measurement has been proved in a previous study and the irradiation impact on the transducer components is here studied. To do so, a radiation resistance experiment was realized in the Arc-Nucleart Institute of Grenoble. It allowed the study of the influence of radiations on the device active and passive components’ characteristics.

Published
2020
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32. Rayleigh Modes Generated by Laser-Ultrasonics at the Film-Substrate Interface for the Study of Adhesion

Author

Robin, Martin, Chrifi Alaoui, Meriem, Jenot, Frédéric, Ouaftouh, Mohammadi, Duquennoy, Marc, Université Polytechnique Hauts-de-France (UPHF), Transduction, Propagation et Imagerie Acoustique - IEMN (TPIA - IEMN), INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), no information, Société Française d'Acoustique, Laboratoire de Mécanique et d'Acoustique, INSA Institut National des Sciences Appliquées Hauts-de-France (INSA Hauts-De-France)-Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Université Polytechnique Hauts-de-France [UPHF], Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN], and Transduction, Propagation et Imagerie Acoustique - IEMN [TPIA - IEMN]

Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], [SPI]Engineering Sciences [physics], [PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph]
Abstract

International audience; Adhesion testing of film-on-substrate structures by surface acoustic waves is a complex issue. Indeed, the fluctuations of some parameters like the film thickness can lead to misinterpretation of the experimental results. Additionally, in laser-ultrasonics, the positions of the generation and detection sources influence the excited and detected parts of the Rayleigh modes as well as the behavior of these surface acoustic waves when the adhesion decreases. While most studies published are focused on the generation of these waves on the film surface, we use an excitation at the interface between the film and the substrate in order to study the adhesion of the structure. To that end, a transparent PVC film with a quasi-constant thickness is placed in direct contact with an aluminum substrate and the laser pulses used are focused through the film at the interface. Finite element simulations are first presented to study the influence of the source position for several adhesion degrees then experimental results complete this work.

Published
2022

35. Combined Next-Generation X-ray and EUV Observations with the FIERCE Mission Concept

Author

Shih, Albert Y., Glesener, Lindsay, Krucker, Säm, Guidoni, Silvina, Christe, Steven, Reeves, Katharine, Gburek, Szymon, Caspi, Amir, Alaoui, Meriem, Allred, Joel, Battaglia, Marina, Baumgartner, Wayne, Dennis, Brian, Drake, James, Goetz, Keith, Golub, Leon, Hannah, Iain, Hayes, Laura, Holman, Gordon, Inglis, Andrew, Ireland, Jack, Kerr, Graham, Klimchuk, James, McKenzie, David, Moore, Christopher, Musset, Sophie, Reep, Jeffrey, Ryan, Daniel, Saint-Hilaire, Pascal, Savage, Sabrina, Schwartz, Richard, Seaton, Daniel, Stęślicki, Marek, and Woods, Thomas

Subjects
X-ray, FIERCE, Solar Physics, Extreme Ultraviolet, Telescope, MIDEX
Abstract

While there have been significant advances in our understanding of impulsive energy release at the Sun through the combination ofRHESSIX-ray observations andSDO/AIA EUV observations, there is a clear science need for significantly improved X-ray and EUV observations. These new observations must capture the full range of emission in flares and CMEs (e.g., faint coronal sources near bright chromospheric sources), connect the intricate evolution of energy release with dynamic changes in the configuration of plasma structures, and identify the signatures of impulsive energy release in even the quiescent Sun. TheFundamentals of Impulsive Energy Release in the Corona Explorer(FIERCE) MIDEX mission concept makes these observations by combining the two instruments previously proposed on theFOXSISMEX mission concept – a focusing hard X-ray spectroscopic imager and a soft X-ray spectrometer – with a high-resolution EUV imager that will not saturate for even intense flares. All instruments observe at high cadence to capture the initiation of solar transient events and the fine time structure within events.FIERCEwould launch in mid-2025, near the peak of the next solar cycle, which is also well timed with perihelions of Parker Solar Probe and Solar Orbiter. The goals ofFIERCEinclude improving our understanding of the genesis of space-weather events, andFIERCEobserations would vitally complement observations by other observatories both near Earth and elsewhere in the heliosphere.

Published
2020
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39. COMMUNICATION MARKETING, CULTURE ET PERFORMANCES DES ENTREPRISES MAROCAINES DANS LES RELATIONS SUD-SUD : ETUDE EXPLORATOIRE

Author

ALAOUI, MERIEM and YASSAFI, MOUSSA

Subjects
Communication, Marketing, Culture, Performances, Afrique, Relations Sud-Sud, Maroc
Abstract

Over the past decades, Morocco has been maintaining and improving its political and economic relations with the African countries. In fact, Morocco is positioning itself as a big brother and a business engine for the whole region. The objective of this paper is to identify the existing relations between Marketing communication and culture with the performance of the Moroccan enterprises serving the African markets. In order to succeed in delivering an impactful communication and improving the return on investment of these Moroccan companies, it is important to understand the relationship between communication and culture be it corporate culture or the culture of the country where the products or services are being sold. Developing those competencies will with no doubt improve Morocco’s business and cultural relations with its neighboring countries in Africa. Keywords: Communication, Marketing, Culture, Performance, Africa, South-South Relations, Morocco Résumé : Le Maroc a une volonté politique et économique claire vis-à-vis de ses relations avec les pays africains. Il se positionne de plus en plus au service de l’Afrique et comme moteur commercial, diplomatique et culturel pour toute la région. L’objectif de cette problématique est d’explorer les relations qui existent entre la communication marketing et la culture avec les performances des entreprises marocaines dans un environnement Sud-Sud. La combinaison de la Communication Marketing avec l’aspect culturel, que ce soit celui lié à l’entreprise marocaine ou au pays Africain ciblé, est une compétence indispensable aux performances des équipes qui travaillent dans un environnement international. Développer cette compétence permettra en effet d’améliorer les relations économiques et culturelles des différents pays., Revue de Management et Cultures, No 2 (2018)

Published
2019
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40. High Frequency Ultrasonic Device development for Non-Destructive Post-Irradiation Examination of the RHF Fuel Element

Author

Chrifi Alaoui, Meriem, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier, Gilles Despaux, and Emmanuel Le Clézio

Subjects
Signal processing, [SPI.OTHER]Engineering Sciences [physics]/Other, High frequency, Rhf, Haute fréquence, Hprr, Radiations, Dispositif ultrasonore, Traitement du signal, Ultrasonic device
Abstract

The future HPRR LEU fuel plates will have to withstand aggressive irradiations leading to a swelling phenomenon. This latter induces structure modifications and impacts the initial inter-plate distance. This distance is investigated, under the access and microscopic resolution constraints, within the PERSEUS Project aiming the development of a non-destructive ultrasonic device. With a thickness of 1 mm to be inserted into the 1.8 mm water channel width of the High flux Reactor (RHF), the device relies upon two ultrasonic transducers connected to an electronic system. It allows time of flight and ultrasonic velocity estimations. The feasibility being already proved, optimizations on components of the measurement chain and signal processing have led to a new device. A developed motorized bench has allowed reproducibility measurements with a 500 nm resolution. Then, a reproducibility devices' radiation resistance experiment, carried out in the Arc-nucleart Institute, demonstrated their parameters stability under 3500 kGray. Experiments were also realized on the RHF fuel element where vertical position, distance and temperature were evaluated, with a 1 µm precision on channel gap thickness. Future works will explore waves ability to be focused in the depth of the plates.; Les prochaines plaques combustibles faiblement enrichies des réacteurs HPRR devront résister à de hautes radiations et dévoileront probablement un gonflement. Ce dernier modifie la structure et influence la distance inter-plaque nominale. La mesure de cette distance à l'ordre micrométrique constitue l'objectif du projet PERSEUS via le développement d'un dispositif ultrasonore non-destructif. Réduit à 1 mm pour s'insérer dans l'interstice inter-plaque de 1.8 mm du Réacteur à Haut Flux (RHF), le dispositif comprend deux transducteurs ultrasonores reliés à un système électronique. Il permet les mesures de temps de vol et de vitesse ultrasonore. La faisabilité de mesure précédemment prouvée, des optimisations de la chaîne de mesure et du traitement du signal ont été intégrées, induisant une nouvelle génération de dispositif. Un banc motorisé a été développé et a permis des mesures de reproductibilité précises à 500 nm. La reproductibilité de résistance aux radiations, expérimentée à l'Institut Arc-Nucléart, a démontré la stabilité des dispositifs sous 3500 kGray. De plus, une expérience de mesure de distance inter-plaque sur l'élément combustible du RHF a permis les mesures de position verticale, de distance inter-plaque et de température avec 1 µm de précision d'épaisseur du canal d'eau. Une étude de faisabilité de focalisation des ondes est prévue pour analyser les plaques en profondeur.

Published
2018

41. Développement d'un dispositif ultrasonore hautes fréquences pour la caractérisation post-irradiation de l'élément combustible du RHF

Author

Chrifi Alaoui, Meriem, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier, Gilles Despaux, and Emmanuel Le Clézio

Subjects
Signal processing, [SPI.OTHER]Engineering Sciences [physics]/Other, High frequency, Rhf, Haute fréquence, Hprr, Radiations, Dispositif ultrasonore, Traitement du signal, Ultrasonic device
Abstract

The future HPRR LEU fuel plates will have to withstand aggressive irradiations leading to a swelling phenomenon. This latter induces structure modifications and impacts the initial inter-plate distance. This distance is investigated, under the access and microscopic resolution constraints, within the PERSEUS Project aiming the development of a non-destructive ultrasonic device. With a thickness of 1 mm to be inserted into the 1.8 mm water channel width of the High flux Reactor (RHF), the device relies upon two ultrasonic transducers connected to an electronic system. It allows time of flight and ultrasonic velocity estimations. The feasibility being already proved, optimizations on components of the measurement chain and signal processing have led to a new device. A developed motorized bench has allowed reproducibility measurements with a 500 nm resolution. Then, a reproducibility devices' radiation resistance experiment, carried out in the Arc-nucleart Institute, demonstrated their parameters stability under 3500 kGray. Experiments were also realized on the RHF fuel element where vertical position, distance and temperature were evaluated, with a 1 µm precision on channel gap thickness. Future works will explore waves ability to be focused in the depth of the plates.; Les prochaines plaques combustibles faiblement enrichies des réacteurs HPRR devront résister à de hautes radiations et dévoileront probablement un gonflement. Ce dernier modifie la structure et influence la distance inter-plaque nominale. La mesure de cette distance à l'ordre micrométrique constitue l'objectif du projet PERSEUS via le développement d'un dispositif ultrasonore non-destructif. Réduit à 1 mm pour s'insérer dans l'interstice inter-plaque de 1.8 mm du Réacteur à Haut Flux (RHF), le dispositif comprend deux transducteurs ultrasonores reliés à un système électronique. Il permet les mesures de temps de vol et de vitesse ultrasonore. La faisabilité de mesure précédemment prouvée, des optimisations de la chaîne de mesure et du traitement du signal ont été intégrées, induisant une nouvelle génération de dispositif. Un banc motorisé a été développé et a permis des mesures de reproductibilité précises à 500 nm. La reproductibilité de résistance aux radiations, expérimentée à l'Institut Arc-Nucléart, a démontré la stabilité des dispositifs sous 3500 kGray. De plus, une expérience de mesure de distance inter-plaque sur l'élément combustible du RHF a permis les mesures de position verticale, de distance inter-plaque et de température avec 1 µm de précision d'épaisseur du canal d'eau. Une étude de faisabilité de focalisation des ondes est prévue pour analyser les plaques en profondeur.

Published
2018

42. <tex-math notation='LaTeX'>$In~Situ$ </tex-math> High-Resolution Measurement of HFR Nuclear Fuel Plates’ Spacing

Author

ZAZ, GHITA, Le Clezio, Emmanuel, Dekious, Ali, Alaoui, Meriem Chrifi, CALZAVARA, YOANN, Despaux, Gilles, INSA Euro-Méditerranée, Institut National des Sciences Appliquées (INSA), Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), and ILL

Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

43. Tenue aux radiations de capteurs ultrasonores haute fréquence dédiés à la mesure de distance au sein de réacteurs à haut flux

Author

Alaoui, Meriem Chrifi, CALZAVARA, YOANN, Le Clézio, Emmanuel, Despaux, Gilles, Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), and ILL

Subjects
[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

44. In-situ high-resolution measurement of RHF nuclear fuel plates' spacing

Author

ZAZ, Ghita, Le Clézio, Emmanuel, Dekious, Ali, Chrifi Alaoui, Meriem, CALZAVARA, YOANN, Despaux, Gilles, INSA Euro-Méditerranée, Institut National des Sciences Appliquées (INSA), Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Matériaux, MicroCapteurs et Acoustique (M2A), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), and ILL

Subjects
ultrasonic transducer, HPRR, RHF, High frequency, high resolution, harsh environment, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; Most of the High Performance Research Reactors (HPRR) are made of plates undergoing a limited swelling during irradiation. Measuring the fuel thickness or the inter-plate distance is then a promissing way to obtain information on the fuel element irradiation history. The experimental constraints are however quite heavy due to the aimed resolution and the element geometry. In order to perform such measurements, a high resolution ultrasonic device was designed. It was thinned down to 1 mm in order to be inserted into the reactor water-channel. The system is then excited with a 120 MHz central frequency burst and the distance measurement is carried out through the ultrasonic waves' time of flight estimation. A series of experiments was performed on a full size irradiated fuel element of the "Institut Laue-Langevin" reactor proving the feasibility of real-time in-situ measurements.

Published
2018

47. Science Objectives of the FOXSI Small Explorer Mission Concept

Author

Shih, Albert Y., Christe, Steven, Alaoui, Meriem, Allred, Joel C., Antiochos, Spiro K., Battaglia, Marina, Buitrago-Casas, Juan Camilo, Caspi, Amir, Dennis, Brian R., Drake, James, Fleishman, Gregory D., Gary, Dale E., Glesener, Lindsay, Grefenstette, Brian, Hannah, Iain, Holman, Gordon D., Hudson, Hugh S., Inglis, Andrew R., Ireland, Jack, Ishikawa, Shin-Nosuke, Natasha Jeffrey, Klimchuk, James A., Kontar, Eduard, Krucker, Sam, Longcope, Dana, Musset, Sophie, Nita, Gelu M., Ramsey, Brian, Ryan, Daniel, Saint-Hilaire, Pascal, Schwartz, Richard A., Vilmer, Nicole, White, Stephen M., and Wilson-Hodge, Colleen

Subjects
FOXSI, Astrophysics::High Energy Astrophysical Phenomena, Physics::Space Physics, Hard X-Ray, Solar Physics, Astrophysics::Solar and Stellar Astrophysics, Telescope, SMEX
Abstract

Impulsive particle acceleration and plasma heating at the Sun, from the largest solar eruptive events to the smallest flares, are related to fundamental processes throughout the Universe. While there have been significant advances in our understanding of impulsive energy release since the advent of RHESSI observations, there is a clear need for new X-ray observations that can capture the full range of emission in flares (e.g., faint coronal sources near bright chromospheric sources), follow the intricate evolution of energy release and changes in morphology, and search for the signatures of impulsive energy release in even the quiescent Sun. The FOXSI Small Explorer (SMEX) mission concept combines state-of-the-art grazing-incidence focusing optics with pixelated solid-state detectors to provide direct imaging of hard X-rays for the first time on a solar observatory. We present the science objectives of FOXSI and how its capabilities will address and resolve open questions regarding impulsive energy release at the Sun. These questions include: What are the time scales of the processes that accelerate electrons? How do flare-accelerated electrons escape into the heliosphere? What is the energy input of accelerated electrons into the chromosphere, and how is super-heated coronal plasma produced?

Published
2016
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48. Radiation resistance of high frequency ultrasonic devices for distance measurement in the RHF.

Author

Lyoussi, A., Giot, M., Carette, M., Jenčič, I., Reynard-Carette, C., Vermeeren, L., Snoj, L., Le Dû, P., Alaoui, Meriem Chrifi, Le Clézio, Emmanuel, Despaux, Gilles, and Calzavara, Yoann

Subjects
NUCLEAR fuel elements, ULTRASONIC equipment, DISTANCE measurement equipment, ELECTRONIC systems, TRANSDUCERS
Abstract

The fuel element plates of research reactors are subjected to swelling phenomena. These structure modifications impact an initial inter-plate distance of 1.8 mm. An ultrasonic device has been developed to investigate this parameter. With a 1 mm thickness, it relies on two transducers linked to an electronic system. The feasibility of the distance measurement has been proved in a previous study and the irradiation impact on the transducer components is here studied. To do so, a radiation resistance experiment was realized in the Arc-Nucleart Institute of Grenoble. It allowed the study of the influence of radiations on the device active and passive components' characteristics. [ABSTRACT FROM AUTHOR]

Published
2020
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