<?xml version="1.0"?>
<!DOCTYPE article
PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.4 20190208//EN"
       "JATS-journalpublishing1.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" article-type="research-article" dtd-version="1.4" xml:lang="en">
 <front>
  <journal-meta>
   <journal-id journal-id-type="publisher-id">Solar-Terrestrial Physics</journal-id>
   <journal-title-group>
    <journal-title xml:lang="en">Solar-Terrestrial Physics</journal-title>
    <trans-title-group xml:lang="ru">
     <trans-title>Solar-Terrestrial Physics</trans-title>
    </trans-title-group>
   </journal-title-group>
   <issn publication-format="online">2500-0535</issn>
  </journal-meta>
  <article-meta>
   <article-id pub-id-type="publisher-id">71293</article-id>
   <article-id pub-id-type="doi">10.12737/stp-101202401</article-id>
   <article-categories>
    <subj-group subj-group-type="toc-heading" xml:lang="ru">
     <subject>Results of current research</subject>
    </subj-group>
    <subj-group subj-group-type="toc-heading" xml:lang="en">
     <subject>Results of current research</subject>
    </subj-group>
    <subj-group>
     <subject>Results of current research</subject>
    </subj-group>
   </article-categories>
   <title-group>
    <article-title xml:lang="en">Observational characteristics of oscillations and waves in and around sunspots. Difficulties in observing and interpreting</article-title>
    <trans-title-group xml:lang="ru">
     <trans-title>Observational characteristics of oscillations and waves in and around sunspots. Difficulties in observing and interpreting</trans-title>
    </trans-title-group>
   </title-group>
   <contrib-group content-type="authors">
    <contrib contrib-type="author">
     <name-alternatives>
      <name xml:lang="ru">
       <surname>Кобанов</surname>
       <given-names>Николай Илларионович</given-names>
      </name>
      <name xml:lang="en">
       <surname>Kobanov</surname>
       <given-names>Nikolay Illarionovich</given-names>
      </name>
     </name-alternatives>
     <email>kobanov@iszf.irk.ru</email>
     <bio xml:lang="ru">
      <p>доктор физико-математических наук;</p>
     </bio>
     <bio xml:lang="en">
      <p>doctor of physical and mathematical sciences;</p>
     </bio>
     <xref ref-type="aff" rid="aff-1"/>
    </contrib>
    <contrib contrib-type="author">
     <name-alternatives>
      <name xml:lang="ru">
       <surname>Челпанов</surname>
       <given-names>Андрей Алексеевич</given-names>
      </name>
      <name xml:lang="en">
       <surname>Chelpanov</surname>
       <given-names>Andrei Alekseevich</given-names>
      </name>
     </name-alternatives>
     <email>a.chlpnv@gmail.com</email>
     <bio xml:lang="ru">
      <p>кандидат физико-математических наук;</p>
     </bio>
     <bio xml:lang="en">
      <p>candidate of physical and mathematical sciences;</p>
     </bio>
     <xref ref-type="aff" rid="aff-2"/>
    </contrib>
   </contrib-group>
   <aff-alternatives id="aff-1">
    <aff>
     <institution xml:lang="ru">Институт солнечно-земной физики СО РАН</institution>
     <city>Иркутск</city>
     <country>Россия</country>
    </aff>
    <aff>
     <institution xml:lang="en">Institute of Solar Terrestrial Physics SB RAS</institution>
     <city>Irkutsk</city>
     <country>Russian Federation</country>
    </aff>
   </aff-alternatives>
   <aff-alternatives id="aff-2">
    <aff>
     <institution xml:lang="ru">Институт солнечно-земной физики СО РАН</institution>
     <city>Иркутск</city>
     <country>Россия</country>
    </aff>
    <aff>
     <institution xml:lang="en">Institute of Solar Terrestrial Physics SB RAS</institution>
     <city>Irkutsk</city>
     <country>Russian Federation</country>
    </aff>
   </aff-alternatives>
   <pub-date publication-format="print" date-type="pub" iso-8601-date="2024-03-26T18:03:15+03:00">
    <day>26</day>
    <month>03</month>
    <year>2024</year>
   </pub-date>
   <pub-date publication-format="electronic" date-type="pub" iso-8601-date="2024-03-26T18:03:15+03:00">
    <day>26</day>
    <month>03</month>
    <year>2024</year>
   </pub-date>
   <volume>10</volume>
   <issue>1</issue>
   <fpage>3</fpage>
   <lpage>9</lpage>
   <history>
    <date date-type="received" iso-8601-date="2023-10-27T00:00:00+03:00">
     <day>27</day>
     <month>10</month>
     <year>2023</year>
    </date>
    <date date-type="accepted" iso-8601-date="2023-12-01T00:00:00+03:00">
     <day>01</day>
     <month>12</month>
     <year>2023</year>
    </date>
   </history>
   <self-uri xlink:href="https://zh-szf.ru/en/nauka/article/71293/view">https://zh-szf.ru/en/nauka/article/71293/view</self-uri>
   <abstract xml:lang="ru">
    <p>This paper summarizes the body of work that we have done over the years on the oscillation processes in sunspots, including their umbra, penumbra, and close vicinity. The study analyzes a number of aspects that impede adequate determining of some characteristics of propagating oscillations and lead to misinterpretation. Using running penumbral waves as an example, we show that their horizontal propagation with decreasing frequency is delusive. The effect is due to different oscillations propagating along magnetic field lines with gradually increasing inclination. This also applies to the three-minute oscillations in the sunspot umbral chromosphere. The change in the inclination of the strips in the half-tone space-time diagrams, which are employed to determine the oscillation propagation velocities along coronal loops, is caused by the projection effect as opposed to real changes in the velocity. We propose to use flare modulation of the natural oscillations of the medium to eliminate the uncertainties that arise while measuring the phase differences between signals of the same parameters, which is employed for estimating wave propagation velocities in the solar atmosphere.</p>
   </abstract>
   <trans-abstract xml:lang="en">
    <p>This paper summarizes the body of work that we have done over the years on the oscillation processes in sunspots, including their umbra, penumbra, and close vicinity. The study analyzes a number of aspects that impede adequate determining of some characteristics of propagating oscillations and lead to misinterpretation. Using running penumbral waves as an example, we show that their horizontal propagation with decreasing frequency is delusive. The effect is due to different oscillations propagating along magnetic field lines with gradually increasing inclination. This also applies to the three-minute oscillations in the sunspot umbral chromosphere. The change in the inclination of the strips in the half-tone space-time diagrams, which are employed to determine the oscillation propagation velocities along coronal loops, is caused by the projection effect as opposed to real changes in the velocity. We propose to use flare modulation of the natural oscillations of the medium to eliminate the uncertainties that arise while measuring the phase differences between signals of the same parameters, which is employed for estimating wave propagation velocities in the solar atmosphere.</p>
   </trans-abstract>
   <kwd-group xml:lang="ru">
    <kwd>sunspots</kwd>
    <kwd>oscillations</kwd>
    <kwd>running penumbral waves</kwd>
    <kwd>flare modulation of oscillations</kwd>
   </kwd-group>
   <kwd-group xml:lang="en">
    <kwd>sunspots</kwd>
    <kwd>oscillations</kwd>
    <kwd>running penumbral waves</kwd>
    <kwd>flare modulation of oscillations</kwd>
   </kwd-group>
   <funding-group>
    <funding-statement xml:lang="ru">The work was financially supported by the Ministry of Science and Higher Education of the Russian Federation</funding-statement>
    <funding-statement xml:lang="en">The work was financially supported by the Ministry of Science and Higher Education of the Russian Federation</funding-statement>
   </funding-group>
  </article-meta>
 </front>
 <body>
  <p></p>
 </body>
 <back>
  <ref-list>
   <ref id="B1">
    <label>1.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Alissandrakis C.E., Dialetis D., Mein P., Schmieder B., Simon G. The Evershed flow in the solar photosphere, chromosphere and chromosphere-corona transition region. Astron. Astrophys. 1988, vol. 201, pp. 339-349.</mixed-citation>
     <mixed-citation xml:lang="en">Alissandrakis C.E., Dialetis D., Mein P., Schmieder B., Simon G. The Evershed flow in the solar photosphere, chromosphere and chromosphere-corona transition region. Astron. Astrophys. 1988, vol. 201, pp. 339-349.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B2">
    <label>2.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Beckers J.M., Tallant P.E. Chromospheric inhomogeneities in sunspot umbrae. Solar Phys. 1969, vol. 7, pp. 351-365. DOI: 10.1007/BF00146140.</mixed-citation>
     <mixed-citation xml:lang="en">Beckers J.M., Tallant P.E. Chromospheric inhomogeneities in sunspot umbrae. Solar Phys. 1969, vol. 7, pp. 351-365. DOI: 10.1007/BF00146140.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B3">
    <label>3.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Bel N., Leroy B. Analytical study of magnetoacoustic gravity waves. Astron. Astrophys. 1977, vol. 55, p. 239.</mixed-citation>
     <mixed-citation xml:lang="en">Bel N., Leroy B. Analytical study of magnetoacoustic gravity waves. Astron. Astrophys. 1977, vol. 55, p. 239.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B4">
    <label>4.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Belov S.A., Molevich N.E., Zavershinskii D.I. Dispersion of slow magnetoacoustic waves in the active region fan loops introduced by thermal misbalance. Solar Phys. 2021, vol. 296, 122. DOI: 10.1007/s11207-021-01868-4.</mixed-citation>
     <mixed-citation xml:lang="en">Belov S.A., Molevich N.E., Zavershinskii D.I. Dispersion of slow magnetoacoustic waves in the active region fan loops introduced by thermal misbalance. Solar Phys. 2021, vol. 296, 122. DOI: 10.1007/s11207-021-01868-4.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B5">
    <label>5.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Bloomfield D.S., Lagg A., Solanki S.K. The nature of running penumbral waves revealed. Astrophys. J. 2007, vol. 671, pp. 1005-1012. DOI: 10.1086/523266.</mixed-citation>
     <mixed-citation xml:lang="en">Bloomfield D.S., Lagg A., Solanki S.K. The nature of running penumbral waves revealed. Astrophys. J. 2007, vol. 671, pp. 1005-1012. DOI: 10.1086/523266.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B6">
    <label>6.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Bogdan T.J., Judge P.G. Observational aspects of sunspot oscillations. Roy. Soc. London Trans. Ser. A, 2006, vol. 364, iss. 1839, pp. 313-331. DOI: 10.1098/rsta.2005.1701.</mixed-citation>
     <mixed-citation xml:lang="en">Bogdan T.J., Judge P.G. Observational aspects of sunspot oscillations. Roy. Soc. London Trans. Ser. A, 2006, vol. 364, iss. 1839, pp. 313-331. DOI: 10.1098/rsta.2005.1701.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B7">
    <label>7.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Botha G., Arber T., Nakariakov V., Zhugzhda Y. Chromospheric resonances above sunspot umbrae. Astrophys. J. 2011, vol. 728, 84. DOI: 10.1088/0004-637X/728/2/84.</mixed-citation>
     <mixed-citation xml:lang="en">Botha G., Arber T., Nakariakov V., Zhugzhda Y. Chromospheric resonances above sunspot umbrae. Astrophys. J. 2011, vol. 728, 84. DOI: 10.1088/0004-637X/728/2/84.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B8">
    <label>8.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Calisir M.A., Yazici H.T., Kilcik A., Yurchyshyn V. Relationships between physical parameters of umbral dots measured for 12 sunspot umbras with the Goode Solar Telescope. Solar Phys. 2023, vol. 298, 103. DOI: 10.1007/s11207-023-02198-3.</mixed-citation>
     <mixed-citation xml:lang="en">Calisir M.A., Yazici H.T., Kilcik A., Yurchyshyn V. Relationships between physical parameters of umbral dots measured for 12 sunspot umbras with the Goode Solar Telescope. Solar Phys. 2023, vol. 298, 103. DOI: 10.1007/s11207-023-02198-3.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B9">
    <label>9.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Chelpanov A.A., Kobanov N.I. Oscillations accompanying a HeI 10830 Å negative flare in a solar facula. Solar Phys. 2018, vol. 293, 157. DOI: 10.1007/s11207-018-1378-2.</mixed-citation>
     <mixed-citation xml:lang="en">Chelpanov A.A., Kobanov N.I. Oscillations accompanying a HeI 10830 Å negative flare in a solar facula. Solar Phys. 2018, vol. 293, 157. DOI: 10.1007/s11207-018-1378-2.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B10">
    <label>10.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Chelpanov A.A., Kobanov N.I. Using flare-induced modulation of three- and five-minute oscillations for studying wave propagation in the solar atmosphere. Solar Phys. 2021, vol. 296, 180. DOI: 10.1007/s11207-021-01910-5.</mixed-citation>
     <mixed-citation xml:lang="en">Chelpanov A.A., Kobanov N.I. Using flare-induced modulation of three- and five-minute oscillations for studying wave propagation in the solar atmosphere. Solar Phys. 2021, vol. 296, 180. DOI: 10.1007/s11207-021-01910-5.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B11">
    <label>11.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Evershed J. Radial movement in sun-spots. Mont. Not. Roy. Astron. Soc. 1909, vol. 69, p. 454. DOI: 10.1093/mnras/69.5.454.</mixed-citation>
     <mixed-citation xml:lang="en">Evershed J. Radial movement in sun-spots. Mont. Not. Roy. Astron. Soc. 1909, vol. 69, p. 454. DOI: 10.1093/mnras/69.5.454.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B12">
    <label>12.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Felipe T., Socas-Navarro H., Khomenko E. Synthetic observations of wave propagation in a sunspot umbra. Astrophys. J. 2014, vol. 795, 9. DOI: 10.1088/0004-637X/795/1/9.</mixed-citation>
     <mixed-citation xml:lang="en">Felipe T., Socas-Navarro H., Khomenko E. Synthetic observations of wave propagation in a sunspot umbra. Astrophys. J. 2014, vol. 795, 9. DOI: 10.1088/0004-637X/795/1/9.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B13">
    <label>13.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">French R.J., Bogdan T.J., Casini R., de Wijn A.G., Judge P.G. First observation of chromospheric waves in a sunspot by DKIST/ViSP: The anatomy of an umbral flash. Astrophys. J. Lett. 2023, vol. 945, L27. DOI: 10.3847/2041-8213/acb8b5.</mixed-citation>
     <mixed-citation xml:lang="en">French R.J., Bogdan T.J., Casini R., de Wijn A.G., Judge P.G. First observation of chromospheric waves in a sunspot by DKIST/ViSP: The anatomy of an umbral flash. Astrophys. J. Lett. 2023, vol. 945, L27. DOI: 10.3847/2041-8213/acb8b5.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B14">
    <label>14.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Giovanelli R.G. Oscillation and waves in a sunspot. Solar Phys. 1972, vol. 27, pp. 71-79. DOI: 10.1007/BF00151771.</mixed-citation>
     <mixed-citation xml:lang="en">Giovanelli R.G. Oscillation and waves in a sunspot. Solar Phys. 1972, vol. 27, pp. 71-79. DOI: 10.1007/BF00151771.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B15">
    <label>15.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Jess D.B., Jafarzadeh S., Keys P.H., Stangalini M., Verth G., Grant S. Waves in the lower solar atmosphere: The dawn of next-generation solar telescopes. Living Rev. Sol. Phys. 2023, vol. 20, A1. DOI: 10.1007/s41116-022-00035-6.</mixed-citation>
     <mixed-citation xml:lang="en">Jess D.B., Jafarzadeh S., Keys P.H., Stangalini M., Verth G., Grant S. Waves in the lower solar atmosphere: The dawn of next-generation solar telescopes. Living Rev. Sol. Phys. 2023, vol. 20, A1. DOI: 10.1007/s41116-022-00035-6.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B16">
    <label>16.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Jess D.B., Reznikova V.E., Van Doorsselaere T., Keys P.H., Mackay D.H. The influence of the magnetic field on running penumbral waves in the solar chromosphere. Astrophys. J. 2013, vol. 779, 168. DOI: 10.1088/0004-637X/779/2/168.</mixed-citation>
     <mixed-citation xml:lang="en">Jess D.B., Reznikova V.E., Van Doorsselaere T., Keys P.H., Mackay D.H. The influence of the magnetic field on running penumbral waves in the solar chromosphere. Astrophys. J. 2013, vol. 779, 168. DOI: 10.1088/0004-637X/779/2/168.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B17">
    <label>17.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Khomenko E., Collados M. Magnetohydrostatic Sunspot Models from Deep Subphotospheric to Chromospheric Layers. Astrophys. J. 2008, vol. 689, pp. 1379-387. DOI: 10.1086/ 592681.</mixed-citation>
     <mixed-citation xml:lang="en">Khomenko E., Collados M. Magnetohydrostatic Sunspot Models from Deep Subphotospheric to Chromospheric Layers. Astrophys. J. 2008, vol. 689, pp. 1379-387. DOI: 10.1086/ 592681.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B18">
    <label>18.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kilcik A., Sarp V., Yurchyshyn V., Rozelot J.-P., Ozguc A. Physical characteristics of umbral dots derived from a high-resolution observations. Solar Phys. 2020, vol. 295, 58. DOI: 10.1007/s11207-020-01618-y.</mixed-citation>
     <mixed-citation xml:lang="en">Kilcik A., Sarp V., Yurchyshyn V., Rozelot J.-P., Ozguc A. Physical characteristics of umbral dots derived from a high-resolution observations. Solar Phys. 2020, vol. 295, 58. DOI: 10.1007/s11207-020-01618-y.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B19">
    <label>19.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kobanov N.I. On Spatial Characteristics of Five-Minute Oscillations in the Sunspot Umbra. Solar Phys. 1990, vol. 125, pp. 25-30. DOI: 10.1007/BF00154775.</mixed-citation>
     <mixed-citation xml:lang="en">Kobanov N.I. On Spatial Characteristics of Five-Minute Oscillations in the Sunspot Umbra. Solar Phys. 1990, vol. 125, pp. 25-30. DOI: 10.1007/BF00154775.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B20">
    <label>20.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kobanov N.I. Measurements of the differential line-of-sight velocity and longitudinal magnetic field on the Sun with CCD photodetector: part I. Modulationless techniques. Instruments and Experimental Techniques. 2001, vol. 44, pp. 524-529.</mixed-citation>
     <mixed-citation xml:lang="en">Kobanov N.I. Measurements of the differential line-of-sight velocity and longitudinal magnetic field on the Sun with CCD photodetector: part I. Modulationless techniques. Instruments and Experimental Techniques. 2001, vol. 44, pp. 524-529.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B21">
    <label>21.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kobanov N.I., Makarchik D.V. Propagating waves in the sunspot umbra chromosphere. Astron. Astrophys. 2004, vol. 424, pp. 671-675. DOI: 10.1051/0004-6361:20035960.</mixed-citation>
     <mixed-citation xml:lang="en">Kobanov N.I., Makarchik D.V. Propagating waves in the sunspot umbra chromosphere. Astron. Astrophys. 2004, vol. 424, pp. 671-675. DOI: 10.1051/0004-6361:20035960.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B22">
    <label>22.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kobanov N.I., Kolobov D.Y., Makarchik D.V. Umbral three-minute oscillations and running penumbral waves. Solar Phys. 2006, vol. 238, pp. 231-244. DOI: 10.1007/s11207-006-0160-z.</mixed-citation>
     <mixed-citation xml:lang="en">Kobanov N.I., Kolobov D.Y., Makarchik D.V. Umbral three-minute oscillations and running penumbral waves. Solar Phys. 2006, vol. 238, pp. 231-244. DOI: 10.1007/s11207-006-0160-z.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B23">
    <label>23.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Kolobov D.Y., Chelpanov A.A., Kobanov N.I. Peculiarity of the oscillation stratification in sunspot penumbrae. Solar Phys. 2016, vol. 291, pp. 3339-3347. DOI: 10.1007/s11207-016-0953-7.</mixed-citation>
     <mixed-citation xml:lang="en">Kolobov D.Y., Chelpanov A.A., Kobanov N.I. Peculiarity of the oscillation stratification in sunspot penumbrae. Solar Phys. 2016, vol. 291, pp. 3339-3347. DOI: 10.1007/s11207-016-0953-7.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B24">
    <label>24.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Lites B.W. Photoelectric observations of chromospheric sunspot oscillations. V. Penumbral oscillations. Astrophys. J. 1988, vol. 334, p. 1054. DOI: 10.1086/166898.</mixed-citation>
     <mixed-citation xml:lang="en">Lites B.W. Photoelectric observations of chromospheric sunspot oscillations. V. Penumbral oscillations. Astrophys. J. 1988, vol. 334, p. 1054. DOI: 10.1086/166898.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B25">
    <label>25.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Lites B.W. Sunspot oscillations - observations and implications. Sunspots. Theory and Observations. Proceedings of the NATO Advanced Research Workshop on the Theory of Sunspots, held in Cambridge, U.K., September 22-27, 1991. 1992, vol. 375, p. 261. DOI: 10.1007/978-94-011-2769-1_12.</mixed-citation>
     <mixed-citation xml:lang="en">Lites B.W. Sunspot oscillations - observations and implications. Sunspots. Theory and Observations. Proceedings of the NATO Advanced Research Workshop on the Theory of Sunspots, held in Cambridge, U.K., September 22-27, 1991. 1992, vol. 375, p. 261. DOI: 10.1007/978-94-011-2769-1_12.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B26">
    <label>26.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Löhner-Böttcher J., Bello González N. Signatures of running penumbral waves in sunspot photospheres. Astron. Astrophys. 2015, vol. 580, A53. DOI: 10.1051/0004-6361/201526230.</mixed-citation>
     <mixed-citation xml:lang="en">Löhner-Böttcher J., Bello González N. Signatures of running penumbral waves in sunspot photospheres. Astron. Astrophys. 2015, vol. 580, A53. DOI: 10.1051/0004-6361/201526230.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B27">
    <label>27.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Madsen C.A., Tian H., DeLuca E.E. Observations of umbral flashes and running sunspot waves with the Interface Region Imaging Spectrograph. Astrophys. J. 2015, vol. 800, A129. DOI: 10.1088/0004-637X/800/2/129.</mixed-citation>
     <mixed-citation xml:lang="en">Madsen C.A., Tian H., DeLuca E.E. Observations of umbral flashes and running sunspot waves with the Interface Region Imaging Spectrograph. Astrophys. J. 2015, vol. 800, A129. DOI: 10.1088/0004-637X/800/2/129.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B28">
    <label>28.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Maltby P., Eriksen G. The Evershed effect as a wave phenomenon. Solar Phys. 1967, vol. 2, pp. 249-257. DOI: 10.1007/ BF00147840.</mixed-citation>
     <mixed-citation xml:lang="en">Maltby P., Eriksen G. The Evershed effect as a wave phenomenon. Solar Phys. 1967, vol. 2, pp. 249-257. DOI: 10.1007/ BF00147840.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B29">
    <label>29.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Milligan R.O., Fleck B., Ireland J., Fletcher L., Dennis B.R. Detection of three-minute oscillations in full-disk Lyα emission during a solar flare. Astrophys. J. Lett. 2017, vol. 848, L8. DOI: 10.3847/2041-8213/aa8f3a.</mixed-citation>
     <mixed-citation xml:lang="en">Milligan R.O., Fleck B., Ireland J., Fletcher L., Dennis B.R. Detection of three-minute oscillations in full-disk Lyα emission during a solar flare. Astrophys. J. Lett. 2017, vol. 848, L8. DOI: 10.3847/2041-8213/aa8f3a.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B30">
    <label>30.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Montesinos B., Thomas J.H. The Evershed effect in sunspots as a siphon flow along a magnetic flux tube. Nature. 1997, vol. 390, pp. 485-487. DOI: 10.1038/37307.</mixed-citation>
     <mixed-citation xml:lang="en">Montesinos B., Thomas J.H. The Evershed effect in sunspots as a siphon flow along a magnetic flux tube. Nature. 1997, vol. 390, pp. 485-487. DOI: 10.1038/37307.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B31">
    <label>31.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Osak B.F., Grigoryev V.M., Kruglov V.I., Skomorovskiy V.I. The Atomated Solar Telescope. Novaya tekhnika v astronomii [New Machinery in Astronomy]. 1979, vol. 6, pp. 84-90. (In Russian).</mixed-citation>
     <mixed-citation xml:lang="en">Osak B.F., Grigoryev V.M., Kruglov V.I., Skomorovskiy V.I. The Atomated Solar Telescope. Novaya tekhnika v astronomii [New Machinery in Astronomy]. 1979, vol. 6, pp. 84-90. (In Russian).</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B32">
    <label>32.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Reznikova V.E., Shibasaki K. Flare quasi-periodic pulsations with growing periodicity. Astron. Astrophys. 2011, vol. 525, A112. DOI: 10.1051/0004-6361/201015600.</mixed-citation>
     <mixed-citation xml:lang="en">Reznikova V.E., Shibasaki K. Flare quasi-periodic pulsations with growing periodicity. Astron. Astrophys. 2011, vol. 525, A112. DOI: 10.1051/0004-6361/201015600.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B33">
    <label>33.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Reznikova V.E., Shibasaki K. Spatial structure of sunspot oscillations observed with SDO/AIA. Astrophys. J. 2012, vol. 756, A35. DOI: 10.1088/0004-637X/756/1/35.</mixed-citation>
     <mixed-citation xml:lang="en">Reznikova V.E., Shibasaki K. Spatial structure of sunspot oscillations observed with SDO/AIA. Astrophys. J. 2012, vol. 756, A35. DOI: 10.1088/0004-637X/756/1/35.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B34">
    <label>34.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Rimmele T.R. On the temporal behaviour of the Evershed effect. Astron. Astrophys. 1994, vol. 290, pp. 972-982.</mixed-citation>
     <mixed-citation xml:lang="en">Rimmele T.R. On the temporal behaviour of the Evershed effect. Astron. Astrophys. 1994, vol. 290, pp. 972-982.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B35">
    <label>35.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Rouppe van der Voort L.H.M., Rutten P.J., Sutterlin P., Sloover P.J., Krijger J.M. La Palma observations of umbral flashes. Astron. Astrophys. 2003, vol. 403, p. 277. DOI: 10.1051/0004-6361:20030237.</mixed-citation>
     <mixed-citation xml:lang="en">Rouppe van der Voort L.H.M., Rutten P.J., Sutterlin P., Sloover P.J., Krijger J.M. La Palma observations of umbral flashes. Astron. Astrophys. 2003, vol. 403, p. 277. DOI: 10.1051/0004-6361:20030237.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B36">
    <label>36.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Schlichenmaier R., Schmidt W. Flow geometry in a sunspot penumbra. Astron. Astrophys. 2000, vol. 358, pp. 1122-1132.</mixed-citation>
     <mixed-citation xml:lang="en">Schlichenmaier R., Schmidt W. Flow geometry in a sunspot penumbra. Astron. Astrophys. 2000, vol. 358, pp. 1122-1132.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B37">
    <label>37.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Settele A., Staude J., Zhugzhda Y. Waves in sunspots: Resonant transmission and the adiabatic coefficient. Solar Phys. 2001, vol. 202, iss. 2, pp. 281-292. DOI: 10.1023/A:10 12225321105.</mixed-citation>
     <mixed-citation xml:lang="en">Settele A., Staude J., Zhugzhda Y. Waves in sunspots: Resonant transmission and the adiabatic coefficient. Solar Phys. 2001, vol. 202, iss. 2, pp. 281-292. DOI: 10.1023/A:10 12225321105.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B38">
    <label>38.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Shine R.A., Title A.M., Tarbell T.D., Smith K., Frank Z.A., Scharmer G. High-resolution observations of the Evershed effect in sunspots. Astrophys. J. 1994, vol. 430, pp. 413-424. DOI: 10.1086/174416.</mixed-citation>
     <mixed-citation xml:lang="en">Shine R.A., Title A.M., Tarbell T.D., Smith K., Frank Z.A., Scharmer G. High-resolution observations of the Evershed effect in sunspots. Astrophys. J. 1994, vol. 430, pp. 413-424. DOI: 10.1086/174416.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B39">
    <label>39.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Sieyra M.V., Krishna Prasad S., Stenborg G., Khomenko E., Van Doorsselaere T., Costa A., Esquivel A., Riedl J.M. Observational and numerical characterization of a recurrent arc-shaped front propagating along a coronal fan. Astron. Astrophys. 2022, vol. 667, A21. DOI: 10.1051/0004-6361/202244454.</mixed-citation>
     <mixed-citation xml:lang="en">Sieyra M.V., Krishna Prasad S., Stenborg G., Khomenko E., Van Doorsselaere T., Costa A., Esquivel A., Riedl J.M. Observational and numerical characterization of a recurrent arc-shaped front propagating along a coronal fan. Astron. Astrophys. 2022, vol. 667, A21. DOI: 10.1051/0004-6361/202244454.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B40">
    <label>40.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Solanki S., Montavon C. Uncombed fields as the source of the broad-band circular polarization of sunspots. Astron. Astrophys. 1993, vol. 275, pp. 283-292.</mixed-citation>
     <mixed-citation xml:lang="en">Solanki S., Montavon C. Uncombed fields as the source of the broad-band circular polarization of sunspots. Astron. Astrophys. 1993, vol. 275, pp. 283-292.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B41">
    <label>41.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Solov’ev A.A., Kirichek E.A. Sunspot as an isolated magnetic structure: Stability and oscillations. Astrophys. Bull. 2008, vol. 63, pp. 169-180. DOI: 10.1134/ S1990341308020077.</mixed-citation>
     <mixed-citation xml:lang="en">Solov’ev A.A., Kirichek E.A. Sunspot as an isolated magnetic structure: Stability and oscillations. Astrophys. Bull. 2008, vol. 63, pp. 169-180. DOI: 10.1134/ S1990341308020077.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B42">
    <label>42.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Solov’ev A.A., Kirichek E.A. Analytical model of an asymmetric sunspot with a steady plasma flow in its penumbra.  Solar Phys. 2016, vol. 291, pp. 1647-1663. DOI: 10.1007/s112 07-016-0922-1.</mixed-citation>
     <mixed-citation xml:lang="en">Solov’ev A.A., Kirichek E.A. Analytical model of an asymmetric sunspot with a steady plasma flow in its penumbra.  Solar Phys. 2016, vol. 291, pp. 1647-1663. DOI: 10.1007/s112 07-016-0922-1.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B43">
    <label>43.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">St. John C.E. Radial motion in sun-spots. Astrophys. J. 1913, vol. 37, p. 322. DOI: 10.1086/142002.</mixed-citation>
     <mixed-citation xml:lang="en">St. John C.E. Radial motion in sun-spots. Astrophys. J. 1913, vol. 37, p. 322. DOI: 10.1086/142002.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B44">
    <label>44.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Stangalini M., Verth G., Fedun V., Aldhafeeri A.A., Jess D.B., Jafarzadeh S., Keys P.H., et al. Large scale coherent magnetohydrodynamic oscillations in a sunspot. Nature Communications. 2022, vol. 13, A479. DOI: 10.1038/s41467-022-28136-8.</mixed-citation>
     <mixed-citation xml:lang="en">Stangalini M., Verth G., Fedun V., Aldhafeeri A.A., Jess D.B., Jafarzadeh S., Keys P.H., et al. Large scale coherent magnetohydrodynamic oscillations in a sunspot. Nature Communications. 2022, vol. 13, A479. DOI: 10.1038/s41467-022-28136-8.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B45">
    <label>45.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Tian C., Petrovay K. Structures in compressible magnetoconvection and the nature of umbral dots. Astron. Astrophys. 2013, vol. 551, A92. DOI: 10.1051/0004-6361/201117361.</mixed-citation>
     <mixed-citation xml:lang="en">Tian C., Petrovay K. Structures in compressible magnetoconvection and the nature of umbral dots. Astron. Astrophys. 2013, vol. 551, A92. DOI: 10.1051/0004-6361/201117361.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B46">
    <label>46.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Turova I.P., Ozhogina O.A., Yurysheva O.V. A flare and umbral flashes in a sunspot. Solar Phys. 2005, vol. 227, pp. 75-88. DOI: 10.1007/s11207-005-1715-0.</mixed-citation>
     <mixed-citation xml:lang="en">Turova I.P., Ozhogina O.A., Yurysheva O.V. A flare and umbral flashes in a sunspot. Solar Phys. 2005, vol. 227, pp. 75-88. DOI: 10.1007/s11207-005-1715-0.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B47">
    <label>47.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Van Doorsselaere T., Srivastava A.K., Antolin P., Magyar N., Vasheghani Farahani S., Tian H., et al. Coronal heating by MHD waves. Space Sci. Rev. 2020, vol. 216, A140. DOI: 10.1007/s11214-020-00770-y.</mixed-citation>
     <mixed-citation xml:lang="en">Van Doorsselaere T., Srivastava A.K., Antolin P., Magyar N., Vasheghani Farahani S., Tian H., et al. Coronal heating by MHD waves. Space Sci. Rev. 2020, vol. 216, A140. DOI: 10.1007/s11214-020-00770-y.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B48">
    <label>48.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Zhao J., Felipe T., Chen R., Khomenko E. Tracing p-mode waves from the photosphere to the corona in active regions. Astrophys. J. Lett. 2016, vol. 830, L17. DOI: 10.3847/2041-8205/830/1/L17.</mixed-citation>
     <mixed-citation xml:lang="en">Zhao J., Felipe T., Chen R., Khomenko E. Tracing p-mode waves from the photosphere to the corona in active regions. Astrophys. J. Lett. 2016, vol. 830, L17. DOI: 10.3847/2041-8205/830/1/L17.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B49">
    <label>49.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Zhugzhda Y.D., Sych R.A. Model of local oscillations in sunspots. Astron. Lett. 2014, vol. 40, pp. 576-593. DOI: 10.1134/ S1063773714090059.</mixed-citation>
     <mixed-citation xml:lang="en">Zhugzhda Y.D., Sych R.A. Model of local oscillations in sunspots. Astron. Lett. 2014, vol. 40, pp. 576-593. DOI: 10.1134/ S1063773714090059.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B50">
    <label>50.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">Zirin H., Stein A. Observations of running penumbral waves. Astrophys. J. 1972, vol. 178, p. L85. DOI: 10.1007/BF001 51771.</mixed-citation>
     <mixed-citation xml:lang="en">Zirin H., Stein A. Observations of running penumbral waves. Astrophys. J. 1972, vol. 178, p. L85. DOI: 10.1007/BF001 51771.</mixed-citation>
    </citation-alternatives>
   </ref>
   <ref id="B51">
    <label>51.</label>
    <citation-alternatives>
     <mixed-citation xml:lang="ru">URL: http://ckp-rf.ru/ckp/3056/ (accessed October 23, 2023).</mixed-citation>
     <mixed-citation xml:lang="en">URL: http://ckp-rf.ru/ckp/3056/ (accessed October 23, 2023).</mixed-citation>
    </citation-alternatives>
   </ref>
  </ref-list>
 </back>
</article>
