Statistical study of the decay-less kink oscillations S. Anfinogentov
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Statistical study of the decay-less kink oscillations S. Anfinogentov1,2 1 University 2 Institute of Warwick, UK of solar-terrestrial physics, Russia MHD Seismology of the Solar Corona in the Era of SDO/AIA ISSI-Beijing 2015 Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 1 / 23 Based on the paper in A&A Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 2 / 23 Outline 1 Two regimes of the coronal loop kink oscillations 2 Problem statement 3 Methods 4 Results 5 Conclusions Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 3 / 23 Decaying oscillations Ashwanden et.al.(1999); Nakariakov et.al.(1999);Schrijver et. al. (1999) Large amplitude > 1 Mm Induced by eruptive events (CME, flare etc) Fast decaying (3-4 periods) Relative rare detected (∼100 events in a year) Intensively studied since 1999 Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 4 / 23 First observations of the decay-less oscillations Wang, T. et al , ApJL, (2012) Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 5 / 23 Decay-less oscillations Video Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 6 / 23 Decay-less oscillations Typical time-distance plot Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 7 / 23 Known properties of the decay-less oscillations G. Nisticò et. al (2013), S. Anfinogentov et. al (2013), G. Nisticò et. al. (2014) Displacement amplitude ∼ 0.2 Mm Velocity amplitude ∼ 2 km · s−1 No connection with eruptive events No significant decay Can be observed during several hours in a certain active region Most probable are the fundamental kink mode I I I Oscillation period depends on the loop length All segments of an oscillating loop are found to oscillate in phase Amplitude maximum is located at the top of the loop Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 8 / 23 Problem statement Step by step description Representative sampling I 21 active regions one by one (NOAA 11637-11657) Constructing a set of time-distance plots from 171Å images for each AR Visual inspection of the plots to identify oscillation patterns Measuring loop length, oscillation period, and amplitude Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 9 / 23 Problem statement Examples of inspected active regions 2013−01−05 2013−01−07 2013−01−04 2013−01−05 800 600 500 0 700 500 300 200 200 AR 11638 100 AR 11637 100 800 900 1000 1100 1200 X [arcsec] 500 400 AR 11639 700 800 900 1000 1100 X [arcsec] 300 AR 11640 200 300 2012−12−31 400 500 X [arcsec] 600 700 400 500 −100 400 0 −500 −600 −100 AR 11641 AR 11642 −700 −200 700 800 900 1000 1100 1200 X [arcsec] Sergey Anfinogentov Y [arcsec] 0 −300 Y [arcsec] −200 −400 −200 −300 −400 AR 11643 −500 −1200−1100−1000 −900 −800 −700 X [arcsec] −1200−1100−1000 −900 −800 −700 X [arcsec] Decay-less kink oscillations 600 700 800 X [arcsec] 900 2013−01−12 200 100 500 2012−12−31 300 Y [arcsec] Y [arcsec] −300 600 −500 600 2013−01−11 −200 −400 0 700 Y [arcsec] 300 −100 Y [arcsec] Y [arcsec] Y [arcsec] 400 400 300 200 100 AR 11644, 11646 0 500 600 700 800 900 1000 X [arcsec] ISSI-Beijing 2015 10 / 23 Methods Is it really possible to identify sub-pixel displacements? Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 11 / 23 Multiple slits perpindicular to the loop 171 Å image Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 12 / 23 Multiple slits perpindicular to the loop Points along the loop path Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 12 / 23 Multiple slits perpindicular to the loop Fitting the loop path as an ellipse in the picture plain Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 12 / 23 Multiple slits perpindicular to the loop Slits perpendicular to the loop path Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 12 / 23 Fitting the parameterss Time-distamce plot of an oscillating event Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 13 / 23 Fitting the parameterss Intensity derivative along the spatial axis Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 13 / 23 Fitting the parameterss Gaussian profile fitting Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 13 / 23 Fitting the parameterss Fitting a sine: x(t) = ξ sin Sergey Anfinogentov 2πt P + φ0 + a1 x + a0 Decay-less kink oscillations ISSI-Beijing 2015 13 / 23 Measuring oscillation parameters Estimating the length of the loop R Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 14 / 23 Results Decay-less low-amplitude oscillations — a common phenomenon Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 15 / 23 Results Active regions where no oscillations were found NOAA 11638 Sergey Anfinogentov NOAA 11647 Decay-less kink oscillations ISSI-Beijing 2015 16 / 23 Results Parameters distribution (70 oscillating loops, NOAA 11637-11657) The distributions of the parameters of oscillating loops 20 15 15 <ξ> = 0.17 Mm σξ = 0.10 Mm 15 <P> = 251 s σP = 133 s <L> = 219 Mm σL = 117 Mm 10 10 10 5 5 5 0 0.1 0.2 0.3 0.4 Amplitude [Mm] Sergey Anfinogentov 0.5 0 100 200 300 400 500 Period [s] 600 Decay-less kink oscillations 0 100 200 300 400 500 Loop length [Mm] ISSI-Beijing 2015 600 17 / 23 Seismological sensitivity Loop length vs oscillation period (70 oscillating loops, NOAA 11637-11657) The parameters of oscillating loops 700 Oscillating period [s] 600 500 400 300 200 100 0 0 Sergey Anfinogentov 100 200 300 400 Loop length [Mm] Decay-less kink oscillations 500 600 ISSI-Beijing 2015 18 / 23 In phase oscillations NOAA 11650 2013−01−05 00:20:12 UT −300 12 10 3 14 12 10 Slit 2 8 10 20 30 40 Time since 2013−01−05 00:00 UT [min] −450 −500 −1050 Slit 1 8 10 20 30 40 Time since 2013−01−05 00:00 UT [min] Disance [Mm] −400 14 2 1 −1000 −950 X [arcsec] −900 −850 Disance [Mm] Y [arcsec] −350 Disance [Mm] Different slits 14 12 10 Slit 3 8 10 20 30 40 Time since 2013−01−05 00:00 UT [min] Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 19 / 23 Conclusions Permanently occur in almost any AR at any time I They were found in 19 of 21 inspected ARs Periodic driver is less probable Standing kink oscillations I I I Oscillation period increases with the length of the loop All segments of the loop oscillate in phase Amplitude maximum is located close to the apex of the loop The promising tool for the MHD seismology of the solar corona I I Observed in any active region Seismologically sensitive Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 20 / 23 Thank you for your attention! Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 21 / 23 Cross correlation analysis (NOAA 11654) Idea Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 22 / 23 Cross correlation analysis (NOAA 11654) Results Sergey Anfinogentov Decay-less kink oscillations ISSI-Beijing 2015 23 / 23
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