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  1. AU="Safrankova, J."
  2. AU="Lanting, Linda L"
  3. AU=Koushik Nikhil S
  4. AU="Culhane, John"
  5. AU="Chippada, Appa Rao"
  6. AU="Hiroki Sato" AU="Hiroki Sato"
  7. AU="Al-Amer Eshraq"
  8. AU="Thanacoody, Ruben"
  9. AU="Lin, Chi-Wei"
  10. AU="Chidambaram, Vignesh"

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Treffer 1 - 10 von insgesamt 62

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  1. Konferenzbeitrag ; Online: sHFAs and favorable conditions for their formation

    Pi, G. / Xirogiannopoulou, N. / Nemecek, Z. / Safrankova, J.

    XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

    2023  

    Abstract: Spontaneous Hot Flow Anomalies (sHFAs) are a kind of foreshock transients. Unlike hot flow anomalies, they are formed in the foreshock region without a clear upstream discontinuity. Nevertheless, the features and their influence on the magnetospheric ... ...

    Abstract Spontaneous Hot Flow Anomalies (sHFAs) are a kind of foreshock transients. Unlike hot flow anomalies, they are formed in the foreshock region without a clear upstream discontinuity. Nevertheless, the features and their influence on the magnetospheric system are the same for these two types of discontinuities. Previous studies revealed that HFA and sHFA preferentially occur under radial IMF conditions. However, our preliminary investigation shows that sHFA rarely occurs during long-lasting radial IMF events. In this study, we will completely check the characteristics of various parameters in the foreshock under different IMF cone angle conditions to reveal the candidate mechanism for this disagreement.
    Sprache Englisch
    Erscheinungsland de
    Dokumenttyp Konferenzbeitrag ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  2. Konferenzbeitrag ; Online: Magnetopause boundary layers under different IMF orientations

    Nemecek, Z. / Safrankova, J. / Pi, G. / Grygorov, K.

    XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

    2023  

    Abstract: Magnetopause is a principal boundary dividing the space controlled by the Earth magnetic field from the incoming solar wind that carries frozen-in interplanetary magnetic field (IMF). Although the magnetopause is often treated as a more or less simple 2D ...

    Abstract Magnetopause is a principal boundary dividing the space controlled by the Earth magnetic field from the incoming solar wind that carries frozen-in interplanetary magnetic field (IMF). Although the magnetopause is often treated as a more or less simple 2D surface, interactions of these two environments lead to creation of boundary layers on both sides of the magnetopause and these layers are filled with a mixture of the magnetospheric and solar wind (magnetosheath) plasma. Mixing of these two plasma populations is facilitated by magnetic reconnection and its rate is controlled, among other factors, by the magnetic shear across the magnetopause. The Earth magnetic field is oriented northward at the subsolar region and thus the great majority of studies deal with the influence of the north-south IMF component on formation of the magnetopause boundary layers. However, pure northward or southward IMF orientation is rather rare and thus the talk surveys results obtained in course of last decades with motivation to stress out that all IMF components should be taken into account and each of them modifies the formation of magnetopause boundary layers its own way. A specific attention will be devoted to the radial IMF conditions and to contribution of processes in the inner magnetosphere on the boundary layer formation and to pressure balance across the whole magnetopause system.
    Thema/Rubrik (Code) 550
    Sprache Englisch
    Erscheinungsland de
    Dokumenttyp Konferenzbeitrag ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  3. Konferenzbeitrag ; Online: Formation of turbulent spectra in the inner heliosphere

    Safrankova, J. / Nemecek, Z. / Nemec, F. / Verscharen, D. / Durovcova, T. / Pitna, A. / Prech, L.

    XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

    2023  

    Abstract: Solar wind turbulence is generated by various processes in the outer corona but it undergoes a rapid evolution in course of the solar wind expansion to the heliosphere. This evolution is more or less well understood from the Mercury orbit until the ... ...

    Abstract Solar wind turbulence is generated by various processes in the outer corona but it undergoes a rapid evolution in course of the solar wind expansion to the heliosphere. This evolution is more or less well understood from the Mercury orbit until the termination shock due to observations of Helios, Ulysses and Voyager but first Parker Solar Probe (PSP) measurements in the inner heliosphere revealed many unexpected features that need a deeper study. The paper presents the comprehensive statistical study of the evolution of compressive and non-compressive magnetic field fluctuations in the inertial and kinetic ranges of frequencies that is based on up to date available PSP data. We analyze solar wind power spectra and their general trends and compare them with Wind observations near 1 au. The first analysis revealed that turbulence is generally decaying with the increasing distance from the source but this trend changes around 0.3-0.4 AU. Moreover, some of the well-established relationships like the spectral steepening with an increasing fluctuation amplitude reverse at near the Sun. We search for possible source(s) of the enhanced fluctuations as well as for physical mechanisms responsible for spectral flattening at the high fluctuation level.
    Sprache Englisch
    Erscheinungsland de
    Dokumenttyp Konferenzbeitrag ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  4. Konferenzbeitrag ; Online: Magnetic Field Power Spectra of Balanced and Imbalanced Solar Wind Turbulence around the Proton Characteristic Scales

    Pitna, A. / Franci, L. / Strauss, D. / Pi, G. / Safrankova, J. / Nemecek, Z.

    XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

    2023  

    Abstract: The nature of the turbulent energy cascade around the proton characteristic scales has been intensely investigated in the last decades. At these scales, i.e., the proton inertial length and proton thermal gyroradius, the character of the fluctuations is ... ...

    Abstract The nature of the turbulent energy cascade around the proton characteristic scales has been intensely investigated in the last decades. At these scales, i.e., the proton inertial length and proton thermal gyroradius, the character of the fluctuations is significantly different with respect to those in the inertial range. For example, intermittency increases, the magnetic field power spectrum steepens, the absolute value of the magnetic helicity gradually increases. Although different explanations for this change of behavior at the proton scales have been suggested (e.g., stochastic heating, proton cyclotron damping, cross-helicity barrier), a full understanding of the dynamical processes that govern the physics of the ion kinetic range is still lacking. In this work, we employ an extensive set of high-cadence measurements of magnetic field from the MFI instrument on board the Wind spacecraft. We estimate the magnetic field power spectra and we analyze them in the framework of the recently-developed technique of Pitna et al. (2021), which corrects for the MFI noise around the Nyquist frequency. We analyze the dependency of the slope below the proton scales on the turbulence power within the inertial range, cross-helicity, and proton plasma beta. We discuss our results with regard to (a) the above-mentioned mechanisms for the origin of the kinetic range, (2) recent observations of the young solar wind by Parker Solar Probe, and (3) tailored 2D hybrid-kinetic simulations of solar wind plasma.
    Thema/Rubrik (Code) 532
    Sprache Englisch
    Erscheinungsland de
    Dokumenttyp Konferenzbeitrag ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  5. Konferenzbeitrag ; Online: Machine learning-based models of the magnetopause location

    Aghabozorgi Nafchi, M. / Nemec, F. / Pi, G. / Nemecek, Z. / Safrankova, J. / Grygorov, K. / Simunek, J.

    XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)

    2023  

    Abstract: Empirical models of the magnetopause location are typically based on the fitting of a large set of identified magnetopause crossings by a predefined function dependent on relevant parameters (solar wind dynamic pressure, interplanetary magnetic field B z ...

    Abstract Empirical models of the magnetopause location are typically based on the fitting of a large set of identified magnetopause crossings by a predefined function dependent on relevant parameters (solar wind dynamic pressure, interplanetary magnetic field B z component, possibly also the tilt angle/others). We remove the assumption of the predefined boundary shape by applying a more general approach based on the artificial neural network. This is used, along with a set of about 40,000 dayside magnetopause crossings identified in the THEMIS A-E, Magion 4, Geotail, and Interball-1 satellite data to model the magnetopause location as a function of relevant parameters and to discuss their influence and the boundary shape. An alternative approach that we consider is an automated identification of the region (magnetosheath/magnetosphere) where the spacecraft occurs at a given location under given conditions. The neural network is then used not to predict the magnetopause radial distance, but rather only the particular plasma region at a given location. The magnetopause boundary is then found as a boundary separating the two regions, i.e., as the boundary where the model region classification changes from the magnetosphere to the magnetosheath. The performance of the obtained models is compared with other empirical magnetopause models.
    Thema/Rubrik (Code) 621
    Sprache Englisch
    Erscheinungsland de
    Dokumenttyp Konferenzbeitrag ; Online
    Datenquelle BASE - Bielefeld Academic Search Engine (Lebenswissenschaftliche Auswahl)

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  6. Buch ; Konferenzbeitrag: 19th Annual Conference of Doctoral Students, WDS'10 "Week of Doctoral Students 2010", Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic, June 1, 2010 to June 4, 2010

    Šafránková, J

    : [proceedings of contributed papers]

    2010  

    Veranstaltung/Kongress Annual Conference of Doctoral Students (19, 2010.06.01-04, Prague) ; WDS'10 (19, 2010.06.01-04, Prague) ; Week of Doctoral Students 2010 (19, 2010.06.01-04, Prague)
    Verfasserangabe J. Šafránková .̤ (ed.)
    Sprache Englisch
    Umfang 204 S., Ill., graph. Darst.
    Verlag Matfyzpress
    Erscheinungsort Praha
    Dokumenttyp Buch ; Konferenzbeitrag
    ISBN 9788073781408 ; 8073781409
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  7. Buch ; Konferenzbeitrag: 19th Annual Conference of Doctoral Students, WDS'10 "Week of Doctoral Students 2010", Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic, June 1, 2010 to June 4, 2010

    Šafránková, J

    : [proceedings of contributed papers]

    2010  

    Veranstaltung/Kongress Annual Conference of Doctoral Students (19, 2010.06.01-04, Prague) ; WDS'10 (19, 2010.06.01-04, Prague) ; Week of Doctoral Students 2010 (19, 2010.06.01-04, Prague)
    Verfasserangabe J. Šafránková .̤ (ed.)
    Sprache Englisch
    Umfang 217 S., Ill., graph. Darst.
    Verlag Matfyzpress
    Erscheinungsort Praha
    Dokumenttyp Buch ; Konferenzbeitrag
    ISBN 9788073781392 ; 8073781395
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  8. Buch ; Konferenzbeitrag: 19th Annual Conference of Doctoral Students, WDS'10 "Week of Doctoral Students 2010", Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic, June 1, 2010 to June 4, 2010

    Šafránková, J

    : [proceedings of contributed papers]

    2010  

    Veranstaltung/Kongress Annual Conference of Doctoral Students (19, 2010.06.01-04, Prague) ; WDS'10 (19, 2010.06.01-04, Prague) ; Week of Doctoral Students 2010 (19, 2010.06.01-04, Prague)
    Verfasserangabe J. Šafránková .̤ (ed.)
    Sprache Englisch
    Umfang 204 S., Ill., graph. Darst.
    Verlag Matfyzpress
    Erscheinungsort Praha
    Dokumenttyp Buch ; Konferenzbeitrag
    ISBN 9788073781415 ; 8073781417
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  9. Buch ; Konferenzbeitrag: 18th Annual Conference of Doctoral Students, WDS'09 "Week of Doctoral Students 2009", Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic, June 2, 2009 to June 5, 2009

    Šafránková, J

    2008  

    Veranstaltung/Kongress Annual Conference of Doctoral Students (18, 2009.06.02-05, Prague) ; WDS'09 (18, 2009.06.02-05, Prague) ; Week of Doctoral Students 2009 (18, 2009.06.02-05, Prague)
    Verfasserangabe J. Šafránková .̤ (ed.)
    Sprache Englisch
    Umfang 209 S., Ill., graph. Darst.
    Verlag Matfyzpress
    Erscheinungsort Praha
    Dokumenttyp Buch ; Konferenzbeitrag
    ISBN 9788073781019 ; 8073781018
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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  10. Buch ; Konferenzbeitrag: 18th Annual Conference of Doctoral Students, WDS'09 "Week of Doctoral Students 2009", Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic, June 2, 2009 to June 5, 2009

    Šafránková, J

    2008  

    Veranstaltung/Kongress Annual Conference of Doctoral Students (18, 2009.06.02-05, Prague) ; WDS'09 (18, 2009.06.02-05, Prague) ; Week of Doctoral Students 2009 (18, 2009.06.02-05, Prague)
    Verfasserangabe J. Šafránková .̤ (ed.)
    Sprache Englisch
    Umfang 267 S., Ill., graph. Darst.
    Verlag Matfyzpress
    Erscheinungsort Praha
    Dokumenttyp Buch ; Konferenzbeitrag
    ISBN 9788073781026 ; 8073781026
    Datenquelle Katalog der Technische Informationsbibliothek Hannover

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