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1.

001-es BibID:BIBFORM102741
035-os BibID:(Wos)000460814000017 (Scopus)85063485972
Első szerző:Gall, Amy C.
Cím:EBIT Observation of Ar Dielectronic Recombination Lines near the Unknown Faint X-Ray Feature Found in the Stacked Spectrum of Galaxy Clusters / Gall, Amy C., Foster Adam R., Silwal, Roshani, Dreiling, Joan M., Borovik, Alexander, Kilgore, Ethan, Ajello, Marco, Gillaspy, John D., Ralchenko, Yuri, Takács, Endre
Dátum:2019
ISSN:1538-4357
Megjegyzések:Motivated by possible atomic origins of the unidentified emission line detected at 3.55?3.57 keV in a stacked spectrum of galaxy clusters, an electron beam ion trap (EBIT) was used to investigate the resonant dielectronic recombination (DR) process in highly charged argon ions as a possible contributor to the emission feature. The He-like Ar DR-induced transition 1s2 2l?1s2l3l· was suggested to produce a 3.62 keV photon near the unidentified line at 3.57 keV and was the starting point of our investigation. The collisional-radiative model NOMAD was used to create synthetic spectra for comparison with both our EBIT measurements and with spectra produced with the AtomDB database/Astrophysical Plasma Emission Code (APEC) used in the Bulbul et al. work. Excellent agreement was found between the NOMAD and EBIT spectra, providing a high level of confidence in the atomic data used. Comparison of the NOMAD and APEC spectra revealed a number of missing features in the AtomDB database near the unidentified line. At an electron temperature of Te = 1.72 keV, the inclusion of the missing lines in AtomDB increases the total flux in the 3.5?3.66 keV energy band by a factor of 2. While important, this extra emission is not enough to explain the unidentified line found in the galaxy cluster spectra.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
atomic processesline: identificationmethods: laboratory: atomictechniques: spectroscopicX-rays: galaxies: clusters
Megjelenés:The Astrophysical Journal. - 872 : 2 (2019), p. 194-202. -
További szerzők:Foster, Adam R. Silwal, Roshani Dreiling, Joan M. Borovik, Alexander Kilgore, Ethan Ajello, Marco Gillaspy, John Dale Ralchenko, Yuri Takács Endre (1965-) (fizikus)
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2.

001-es BibID:BIBFORM097501
035-os BibID:(cikkazonosító)202
Első szerző:Kiss Gábor Gyula (kísérleti fizikus)
Cím:Low-energy Measurement of the 96Zr(α,n)99Mo Reaction Cross Section and Its Impact on Weak r-process Nucleosynthesis / G. G. Kiss, T. N. Szegedi, P. Mohr, M. Jacobi, Gy. Gyürky, R. Huszánk, A. Arcones
Dátum:2021
ISSN:0004-637X 1538-4357
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:The Astrophysical Journal. - 908 : 2 (2021), p. 1-7. -
További szerzők:Szegedi Tibor Norbert (1992-) (okleveles fizikus) Mohr, P. Jacobi, M. Gyürky Gy. Huszánk Róbert (vegyész kutató) Arcones, A.
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3.

001-es BibID:BIBFORM042154
Első szerző:Laming, J. Martin
Cím:The Polar Regions of Cassiopeia A: The Aftermath of a Gamma-Ray Burst? / J. Martin Laming, Una Hwang, Balint Radics, Gergely Lekli, Endre Takács
Dátum:2006
ISSN:0004-637X
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Astrophysical Journal. - 644 : 1 (2006), p. 260-273. -
További szerzők:Hwang, Una Radics Bálint Lekli Gergely Takács Endre (1965-) (fizikus)
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4.

001-es BibID:BIBFORM114339
035-os BibID:(WoS)000552323800001 (Scopus)85088963481
Első szerző:Oxley, William
Cím:Standing MHD Waves in a Magnetic Slab Embedded in an Asymmetric Magnetic Plasma Environment: Surface Waves / William Oxley, Noémi Kinga Zsámberger, Róbert Erdélyi
Dátum:2020
ISSN:1538-4357
Megjegyzések:Building on a previous study that analyzed standing surface waves in magnetic slabs embedded in a non-magnetic external environment, in this study the model is generalized and external magnetic fields are added. The slab is assumed to be thin, with weak magnetic asymmetry. The frequencies of the standing harmonic modes are derived to leading order in the small quantities representing the thin slab width and the weak asymmetry. It is found that the frequencies are more sensitive to changes to the width of the slab than changes in the magnetic asymmetry. The frequency ratio of the first harmonic to the fundamental mode is derived, along with the amplitude difference between the two sides of the slab, as these may be observable quantities that can be compared with observational results and applied to carry out solar magnetoseismology.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Nap
napfizika
magnetohidrodinamika
MHD
protuberancia
naplégkör
hullámok
Megjelenés:The Astrophysical Journal. - 898 : 1 (2020), p. 19-31. -
További szerzők:Zsámberger Noémi Kinga (1991-) (csillagász) Erdélyi Róbert
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5.

001-es BibID:BIBFORM103261
035-os BibID:(cikkazonosító)109 (WOS)000629751100018 (Scopus)85081623427
Első szerző:Oxley, William
Cím:Standing MHD waves in a magnetic slab embedded in an asymmetric plasma environment: slow surface waves / William Oxley, Noémi Kinga Zsámberger, Róbert Erdélyi
Dátum:2020
ISSN:1538-4357
Megjegyzések:The field of solar magnetoseismology ( SMS) is heavily reliant upon our understanding of magnetohydrodynamic (MHD) waves that occur in many solar features. Building on previous studies of propagating MHD waves in a magnetic slab embedded in a nonmagnetic asymmetric environment, in this study we assume a line-tying boundary condition and use analytical techniques to derive the dispersion relation for linear standing MHD oscillations. The slab is first assumed thin, with arbitrary asymmetry, in order to derive the frequencies of the standing harmonic modes for both slow quasi-sausage and slow quasi-kink waves. Besides this, the asymmetry is assumed to be weak in order to determine the frequency dependence on the width of the slab and the asymmetry of the system, to leading order. For both the quasi-sausage and quasi-kink modes, the derived eigenfrequencies show that the dependence on the asymmetry in the system is much weaker than the dependence on the width of the slab. Using the eigenfrequencies, other observable quantities are derived (such as, e.g., the frequency ratio) providing an opportunity to use SMS to infer background diagnostics of the system.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
STRUCTURED ATMOSPHERE
OSCILLATIONS
PROPAGATION
Megjelenés:The Astrophysical Journal. - 890 : 2 (2020), p. 1-12. -
További szerzők:Zsámberger Noémi Kinga (1991-) (csillagász) Erdélyi Róbert
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6.

001-es BibID:BIBFORM114341
035-os BibID:(WoS)000835781800001 (Scopus)85135636493 (cikkazonosító)155
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:Solar Magneto-seismology of a Magnetic Slab in an Asymmetric Magnetic Environment / Noémi Kinga Zsámberger, Róbert Erdélyi
Dátum:2022
ISSN:0004-637X
Megjegyzések:Diagnosing the solar atmospheric plasma remains one of the major challenges in solar physics. In recent years, new methods have been developed to apply the powerful concept of solar magneto-seismology (SMS) to obtain information about plasma parameters in solar structures guiding magnetohydrodynamic (MHD) waves that would otherwise be difficult to measure. This paper uses the Cartesian model of a magnetic slab placed in an asymmetric magnetic environment to generalize recently discovered SMS techniques. Utilizing the fact that the asymmetric environment changes the character of the classical kink and sausage eigenmodes, we describe two spatial seismology methods built upon this mixed character of quasi-sausage and quasi-kink modes. First, we present the amplitude ratio technique, which compares the oscillation amplitudes measured at the two boundaries of the slab, and we provide expressions to estimate the internal Alfvén speed in the thin slab and in the incompressible plasma approximations. The second main technique relies on the changed distribution of wave power throughout the slab under the effect of waveguide asymmetry. This minimum perturbation shift technique is then also utilized to provide Alfvén speed estimates that depend on the plasma and magnetic parameters of the environment, as well as the measured slab width and oscillation frequency. Finally, we perform a brief investigation of how the amplitude ratio and the minimum perturbation shift depend on the different sources of waveguide asymmetry, and illustrate our findings with numerical results.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Nap
napfizika
magnetohidrodinamika
MHD
naplégkör
korona szeizmológia
hullámok
napkorona
Megjelenés:Astrophysical Journal. - 934 : 2 (2022), p. 1-10. -
További szerzők:Erdélyi Róbert
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7.

001-es BibID:BIBFORM114338
035-os BibID:(WoS)000536089700001 (Scopus)85085332004
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:Magnetoacoustic Waves in a Magnetic Slab Embedded in an Asymmetric Magnetic Environment. II. Thin and Wide Slabs, Hot and Cold Plasmas / Noémi Kinga Zsámberger, Róbert Erdélyi
Dátum:2020
ISSN:1538-4357
Megjegyzések:Wave propagation in magnetically structured atmospheres is a thoroughly studied, yet practically inexhaustible, well of investigations in the field of solar magneto-seismology. A simple but powerful example is the examination of wave behavior in a magnetic slab. Our previous study used an analytical approach to derive the general dispersion relation for magnetoacoustic waves in a magnetic slab of homogeneous plasma, which was enclosed in an asymmetric magnetic environment. In the present study, we focus on the analysis of wave propagation in various limiting cases applicable to solar and space plasma physics or astrophysics. The thin- and wide-slab approximations, as well as the limits of low and high plasma ? values, are considered. Utilizing the fact that in a weakly asymmetric slab the dispersion relation can be decoupled, the behavior of quasi-sausage and quasi-kink modes is studied in further analytical and numerical detail, and their avoided crossings are described. The results highlight how asymmetry influences the wave properties, e.g., the phase speed of eigenmodes, depending on the ratios of external to internal densities and magnetic fields on the two sides. Notably, the phase speeds of surface modes will converge to different values for the quasi-sausage and quasi-kink modes in the wide-slab limit, and cutoff frequencies are introduced with respect to both surface and body modes, in thin as well as wide slabs, beyond which the solutions become leaky. These obtained properties of MHD wave behavior could be measured with suitable high-resolution instruments in the future.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
naplégkör
protuberancia
magnetohidrodinamika
MHD
korona szeizmológia
hullámok
fényes mágneses pontok (MBP)
Megjelenés:The Astrophysical Journal. - 894 : 2 (2020), p. 123-141. -
További szerzők:Erdélyi Róbert
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8.

001-es BibID:BIBFORM114336
035-os BibID:(WoS)000423849000011 (Scopus)85041819758
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:Magneto-acoustic Waves in a Magnetic Slab Embedded in an Asymmetric Magnetic Environment: The Effects of Asymmetry / Zsámberger Noémi Kinga ; Matthew Allcock ; Erdélyi Róbert
Dátum:2018
ISSN:1538-4357
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
magnetohidrodinamika
napkorona
Nap
fotoszféra
hullámok
MHD
Megjelenés:The Astrophysical Journal. - 853 : 2 (2018), p. 136-148. -
További szerzők:Matthew Allcock Erdélyi Róbert
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9.

001-es BibID:BIBFORM114340
035-os BibID:(WoS)000607945400001 (Scopus)85100148543
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:Magnetoacoustic Waves in a Magnetic Slab Embedded in an Asymmetric Magnetic Environment. III. Applications to the Solar Atmosphere / Noémi Kinga Zsámberger, Róbert Erdélyi
Dátum:2021
ISSN:1538-4357
Megjegyzések:Analytical and numerical modeling of the behavior of magnetohydrodynamic waves in various magnetic geometries can offer a valuable contribution to the field of solar magnetoseismology. Based on analytical results from our previous studies, here we illustrate a few solar applications of these findings concerning the propagation of magnetoacoustic waves in a magnetic slab embedded in an asymmetric environment. Bearing in mind the simplifying assumptions made, this asymmetric model incorporating external magnetic fields can be used to describe a wide variety of multilayered solar features, some of which are observable and have already been studied in solar structures. Specific potential applications are: prominences, polar plumes and their environment, magnetic bright points, and light bridges, as well as adjacent large-scale layers in the solar atmosphere (e.g., the photosphere-interface region-corona triad, or the chromosphere?transition region-corona group). In these individual cases, the appropriate dispersion relations are derived and solved. The obtained wave propagation solutions may serve (i) not just as impetus to be confirmed by high-resolution observations but (ii) also to be exploited for further diagnostic purposes by solar magnetoseismology of these frequently studied magnetic structures.
Analytical and numerical modeling of the behavior of magnetohydrodynamic waves in various magnetic geometries can offer a valuable contribution to the field of solar magnetoseismology. Based on analytical results from our previous studies, here we illustrate a few solar applications of these findings concerning the propagation of magnetoacoustic waves in a magnetic slab embedded in an asymmetric environment. Bearing in mind the simplifying assumptions made, this asymmetric model incorporating external magnetic fields can be used to describe a wide variety of multilayered solar features, some of which are observable and have already been studied in solar structures. Specific potential applications are: prominences, polar plumes and their environment, magnetic bright points, and light bridges, as well as adjacent large-scale layers in the solar atmosphere (e.g., the photosphere -interface region-corona triad, or the chromosphere-transition region-corona group). In these individual cases, the appropriate dispersion relations are derived and solved. The obtained wave propagation solutions may serve (i) not just as impetus to be confirmed by high-resolution observations but (ii) also to be exploited for further diagnostic purposes by solar magnetoseismology of these frequently studied magnetic structures.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Nap
magnetohidrodinamika
MHD
naplégkör
protuberancia
fényes mágneses pontok (MBP)
napfolt
hullámok
Megjelenés:The Astrophysical Journal. - 906 : 2 (2021), p. 122-139. -
További szerzők:Erdélyi Róbert
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10.

001-es BibID:BIBFORM114343
035-os BibID:(WoS)000859291200001 (Scopus)85139380791
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:Magnetohydrodynamic Waves in an Asymmetric Magnetic Slab with Different External Flows / Zsámberger Noémi Kinga; Carmen M. Sánchez Montoya; Erdélyi Róbert
Dátum:2022
ISSN:0004-637X
Megjegyzések:Building on recent studies of the Kelvin-Helmholtz instability (KHI) in the solar atmosphere, we investigate a simple analytical model that can further our understanding of how the presence of bulk flows influences the propagation of magnetohydrodynamic (MHD) waves. Our model builds on a series of recent works on stationary MHD waveguides and looks at a magnetic slab with a density asymmetry, as well as asymmetric background steady flows present in its environment. We obtained approximate solutions to the dispersion relation for the important and applicable limiting cases of a thin or a wide slab, as well as low- and high-? plasmas. We also explored the relation between the angular frequency of trapped MHD waves, the limit for the onset of the KHI, and small parameters describing the flow and density asymmetries. Our analytical investigation is complemented by a numerical analysis for various bulk flow speeds and slab widths. Both these avenues of study reveal that the flow field asymmetry has an important effect on both the cutoff frequencies and the stability of trapped MHD waves in the slab configuration.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Nap
napfizika
magnetohidrodinamika
MHD
naplégkör
fényes mágneses pontok (MBP)
hullámok
Megjelenés:Astrophysical Journal. - 937 : 1 (2022), p. 23-34. -
További szerzők:Sánchez Montoya, Carmen M. Erdélyi Róbert
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11.

001-es BibID:BIBFORM114342
035-os BibID:(WoS)000839946400001 (Scopus)85136063082
Első szerző:Zsámberger Noémi Kinga (csillagász)
Cím:MHD Wave Propagation and the Kelvin-Helmholtz Instability in an Asymmetric Magnetic Slab System / Zsámberger Noémi Kinga; Yihui Tong; Asztalos Balázs; Erdélyi Róbert
Dátum:2022
ISSN:0004-637X
Megjegyzések:Magnetohydrodynamic waves are ubiquitously detected in the finely structured solar atmosphere. At the same time, our Sun is a highly dynamic plasma environment, giving rise to flows of various magnitudes, which can lead to the instability of waveguides. Recent studies have employed the method of introducing waveguide asymmetry to generalize "classical" symmetric descriptions of the fine structuring within the solar atmosphere, with some of them introducing steady flows as well. Building on these recent studies, here we investigate the magnetoacoustic waves guided by a magnetic slab within an asymmetric magnetic environment, in which the slab is under the effect of a steady flow. We provide an analytical investigation of how the phase speeds of the guided waves are changed, and where possible, determine the limiting flow speeds required for the onset of the Kelvin-Helmholtz instability. Furthermore, we complement the study with initial numerical results, which allows us to demonstrate the validity of our approximations and extend the investigation to a wider parameter regime. This configuration is part of a series of studies aimed to generalize, step-by-step, well-known symmetric waveguide models and understand the additional physics stemming from introducing further sources of asymmetry.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Nap
napfizika
magnetohidrodinamika
MHD
napkorona
kromoszféra
naplégkör
Megjelenés:Astrophysical Journal. - 935 : 1 (2022), p. 41-53. -
További szerzők:Tong, Yihui Asztalos Balázs Erdélyi Róbert
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