Solar U- and J-Bursts at the Decameter Waves
The first solar U- and J-bursts observed with the UTR-2 radiotelescope at the decameter wavelengths in 2003–2004 are reported. During that period more than 50 J-bursts and only 7 U-bursts were recorded. It is the first case of ground based observations of J- and U-bursts with turning frequencies ran...
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Дата: | 2012 |
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Видавничий дім «Академперіодика»
2012
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Назва журналу: | Radio physics and radio astronomy |
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oai:ri.kharkov.ua:article-4892012-11-16T12:11:13Z Solar U- and J-Bursts at the Decameter Waves Солнечные U- и J-всплески на декаметровых волнах Dorovskyy, V. V. Melnik, V. M. Konovalenko, O. O. Rucker, H. O. Abranin, E. P. Lecacheux, A. The first solar U- and J-bursts observed with the UTR-2 radiotelescope at the decameter wavelengths in 2003–2004 are reported. During that period more than 50 J-bursts and only 7 U-bursts were recorded. It is the first case of ground based observations of J- and U-bursts with turning frequencies ranging between 10 and 25 MHz. The harmonic structure of J-bursts in the form of Jb–J pairs similar to well known Type IIIb–III pairs was first found. The mean harmonic ratio appeared to be 1.8. Also a group of J-bursts with unusual Turning Frequency Drift (TFD) of –2 kHz/s was detected. Such TFD corresponds to the coronal loop elevation velocity of about 60 km/s. Coronal loops with similar elevation velocities were also detected by SOHO/LASCO coronagraph in white light. The dynamic spectra of unusual U- and J-bursts are shown. Simplified model of the coronal loop in the form of semi-circle was created on the base of the U-burst dynamic spectrum and the Newkirk coronal density model. With this loop model the linear velocity of the source along the loop, the height of the turning frequency point and the geometrical size of the loop were calculated. Приведены результаты первых наблюдений солнечных U- и J-всплесков на радиотелескопе УТР-2 в декаметровом диапазоне длин волн в 2003–2004 гг. За указанный период было зарегистрировано более 50 J-всплесков и только 7 U-всплесков. Это первый случай наземного наблюдения U-всплесков с частотами поворота в диапазоне между 10 и 25 МГц. Обнаружена гармоническая структура J-всплесков в виде Jb–J пар, аналогичных парам всплесков IIIb–III типа. Среднее отношение частот гармоник оказалось равным 1.8. Зарегистрирована группа J-всплесков с необычной скоростью дрейфа частот поворота (TFD) –2 кГц/с, что соответствует скорости подъема корональной арки около 60 км/с. Арки с такой скоростью подъема были обнаружены также коронографом SOHO/LASCO в видимом свете. Приведены динамические спектры необычных U- и J-всплесков. По динамическому спектру U-всплеска с хорошо развитыми восходящей и нисходящей ветвями построена упрощенная модель корональной арки в виде полуокружности. На основании этой модели найдены линейная скорость перемещения источника вдоль магнитной арки, высота точки поворота в короне, геометрические размеры арки. Видавничий дім «Академперіодика» 2012-11-14 Article Article application/pdf http://rpra-journal.org.ua/index.php/ra/article/view/489 РАДИОФИЗИКА И РАДИОАСТРОНОМИЯ; Vol 15, No 1 (2010); 5 RADIO PHYSICS AND RADIO ASTRONOMY; Vol 15, No 1 (2010); 5 РАДІОФІЗИКА І РАДІОАСТРОНОМІЯ; Vol 15, No 1 (2010); 5 2415-7007 1027-9636 rus http://rpra-journal.org.ua/index.php/ra/article/view/489/54 |
institution |
Radio physics and radio astronomy |
collection |
OJS |
language |
rus |
format |
Article |
author |
Dorovskyy, V. V. Melnik, V. M. Konovalenko, O. O. Rucker, H. O. Abranin, E. P. Lecacheux, A. |
spellingShingle |
Dorovskyy, V. V. Melnik, V. M. Konovalenko, O. O. Rucker, H. O. Abranin, E. P. Lecacheux, A. Solar U- and J-Bursts at the Decameter Waves |
author_facet |
Dorovskyy, V. V. Melnik, V. M. Konovalenko, O. O. Rucker, H. O. Abranin, E. P. Lecacheux, A. |
author_sort |
Dorovskyy, V. V. |
title |
Solar U- and J-Bursts at the Decameter Waves |
title_short |
Solar U- and J-Bursts at the Decameter Waves |
title_full |
Solar U- and J-Bursts at the Decameter Waves |
title_fullStr |
Solar U- and J-Bursts at the Decameter Waves |
title_full_unstemmed |
Solar U- and J-Bursts at the Decameter Waves |
title_sort |
solar u- and j-bursts at the decameter waves |
title_alt |
Солнечные U- и J-всплески на декаметровых волнах |
description |
The first solar U- and J-bursts observed with the UTR-2 radiotelescope at the decameter wavelengths in 2003–2004 are reported. During that period more than 50 J-bursts and only 7 U-bursts were recorded. It is the first case of ground based observations of J- and U-bursts with turning frequencies ranging between 10 and 25 MHz. The harmonic structure of J-bursts in the form of Jb–J pairs similar to well known Type IIIb–III pairs was first found. The mean harmonic ratio appeared to be 1.8. Also a group of J-bursts with unusual Turning Frequency Drift (TFD) of –2 kHz/s was detected. Such TFD corresponds to the coronal loop elevation velocity of about 60 km/s. Coronal loops with similar elevation velocities were also detected by SOHO/LASCO coronagraph in white light. The dynamic spectra of unusual U- and J-bursts are shown. Simplified model of the coronal loop in the form of semi-circle was created on the base of the U-burst dynamic spectrum and the Newkirk coronal density model. With this loop model the linear velocity of the source along the loop, the height of the turning frequency point and the geometrical size of the loop were calculated. |
publisher |
Видавничий дім «Академперіодика» |
publishDate |
2012 |
url |
http://rpra-journal.org.ua/index.php/ra/article/view/489 |
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first_indexed |
2024-05-26T06:33:17Z |
last_indexed |
2024-05-26T06:33:17Z |
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