Effects of Stratification and Flows on P1/P2 Ratios and Anti-node Shifts Within Closed Loop Structures

Erdélyi, R.; Hague, A.; Nelson, C. J.
January 2014
Solar Physics;Jan2014, Vol. 289 Issue 1, p167
Academic Journal
The solar atmosphere is a dynamic environment, constantly evolving to form a wide range of magnetically dominated structures (coronal loops, spicules, prominences, etc.) which cover a significant percentage of the surface at any one time. Oscillations and waves in many of these structures are now widely observed and have led to the new analytic technique of solar magneto-seismology, where inferences of the background conditions of the plasma can be deduced by studying magneto-hydrodynamic (MHD) waves. Here, we generalise a novel magneto-seismological method designed to infer the density distribution of a bounded plasma structure from the relationship of its fundamental and subsequent harmonics. Observations of the solar atmosphere have emphatically shown that stratification, leading to complex density profiles within plasma structures, is common thereby rendering this work instantly accessible to solar physics. We show, in a dynamic waveguide, how the period ratio differs from the idealised harmonic ratios prevalent in homogeneous structures. These ratios show strong agreement with recent observational work. Next, anti-node shifts are also analysed. Using typical scaling parameters for bulk flows within atmospheric waveguides, e.g., coronal loops, it is found that significant anti-node shifts can be predicted, even to the order of 10 Mm. It would be highly encouraged to design specific observations to confirm the predicted anti-node shifts and apply the developed theory of solar magneto-seismology to gain more accurate waveguide diagnostics of the solar atmosphere.


Related Articles

  • Three-Dimensional MHD Wave Propagation and Conversion to Alfvén Waves near the Solar Surface. I. Direct Numerical Solution. Cally, P.; Goossens, M. // Solar Physics;Sep2008, Vol. 251 Issue 1/2, p251 

    The efficacy of fast – slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis, and direct numerical simulation. These show that...

  • Time — Distance Modelling in a Simulated Sunspot Atmosphere. Moradi, H.; Cally, P. // Solar Physics;Sep2008, Vol. 251 Issue 1/2, p309 

    In time – distance helioseismology, wave travel times are measured from the cross-correlation between Doppler velocities recorded at any two locations on the solar surface. However, one of the main uncertainties associated with such measurements is how to interpret observations made in...

  • Comparing Simulations of Rising Flux Tubes Through the Solar Convection Zone with Observations of Solar Active Regions: Constraining the Dynamo Field Strength. Weber, M. A.; Fan, Y.; Miesch, M. S. // Solar Physics;Oct2013, Vol. 287 Issue 1/2, p239 

    We study how active-region-scale flux tubes rise buoyantly from the base of the convection zone to near the solar surface by embedding a thin flux tube model in a rotating spherical shell of solar-like turbulent convection. These toroidal flux tubes that we simulate range in magnetic field...

  • Variability of Solar Five-Minute Oscillations in the Corona as Observed by the Extreme Ultraviolet Spectrophotometer (ESP) on the Solar Dynamics Observatory/Extreme Ultraviolet Variability Experiment (SDO/EVE) Didkovsky, L.; Kosovichev, A.; Judge, D.; Wieman, S.; Woods, T. // Solar Physics;Oct2013, Vol. 287 Issue 1/2, p171 

    Solar five-minute oscillations have been detected in the power spectra of two six-day time intervals from soft X-ray measurements of the Sun observed as a star using the Extreme Ultraviolet Spectrophotometer (ESP) onboard the Solar Dynamics Observatory (SDO)/ Extreme Ultraviolet Variability...

  • Variations of the dipole magnetic moment of the sun during the solar activity cycle. Livshits, I. M.; Obridko, V. N. // Astronomy Reports;Nov2006, Vol. 50 Issue 11, p926 

    Observations of the large-scale solar magnetic field (synoptic maps) and measurements of the magnetic field of the Sun as a star (the total magnetic field) are used to determine the dipole magnetic moment and direction of the dipole field for three successive solar cycles. Both the magnetic...

  • Multifractal Analysis Of Solar Magnetograms. Abramenko, Valentyna I. // Solar Physics;May2005, Vol. 228 Issue 1/2, p29 

    As solar observational techniques improve, fine small-scale structures observed on the solar surface become more pronounced. Complex filigree structures of solar granulation, sunspots, photospheric magnetic and velocity fields cannot be described adequately by a single parameter (e.g., filling...

  • Sampling the Coronal Magnetic Field. Ballai, Istvan // AIP Conference Proceedings;9/10/2007, Vol. 934 Issue 1, p44 

    High resolution observations of the last decade made it clear that the magnetic field is, without doubt, one of the most important quantities of the solar atmosphere. Magnetic field controls the dynamics, stability and thermal state of the plasma. At the same time, magnetic field is connecting...

  • Solar Magnetism: The State of Our Knowledge and Ignorance. Parker, E. N. // Space Science Reviews;Dec2008, Vol. 144 Issue 1-4, p15 

    We review some longstanding scientific mysteries related to solar magnetism, with final attention to the mystery of the “turbulent diffusion” essential for the theoretical α ω-dynamo that is believed to be the source of the magnetic fields of the Sun. Fundamental difficulties...

  • Effects of Magnetic Fields in the Solar Atmosphere on Global Oscillations. Pintér, Balázs; Erdélyi, Robert // Space Science Reviews;Jul2011, Vol. 158 Issue 2-4, p471 

    Helioseismology is practically the only efficient experimental way of probing the solar interior. Without it, the results of theoretical solar models would remain untested and, consequently, less reliable when applying them for investigating remote stars. Hence, having a firm understanding of...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics