Advertisement

Penumbral Microjets in Sunspot Chromospheres: Evidence of Magnetic Reconnection

  • Yukio Katsukawa
Chapter
First Online:
Part of the Astrophysics and Space Science Library book series (ASSL, volume 449)

Abstract

It is not too much to say that the greatest achievement of the Hinode Solar Optical Telescope is observational demonstration of active plasma ejections (i.e., jets) occurring everywhere in the solar chromosphere. Among them, the penumbral microjets newly discovered by Hinode are a small-scale jet phenomenon that occurs frequently in the chromosphere above a sunspot penumbra. They are important because we can show strong evidence supporting magnetic reconnection as a driver of chromospheric jets because we can observe in detail the magnetic field and velocity structures around the site where a penumbral microjet occurs. The observation of penumbral microjets gave rise to strong recognition of the importance of magnetic reconnection in driving transient energy release even when the magnetic fields are not completely antiparallel. Recent progress in high-resolution observations of transition regions and coronae suggests the possible influence of penumbral microjets in the atmosphere outer than the chromosphere.

Keywords

Sun Hinode Sun: chromosphere Jets Sunspots 
This is a preview of subscription content, log in to check access.

Notes

Acknowledgements

I’d like to thank all the people who contributed to the development and operation of the Hinode SOT in Japan for 10 years, especially Drs. S. Tsuneta, T. Shimizu, Y. Suematsu, K. Ichimoto, T. J. Okamoto, and M. Kubo, and Mr. T. Bando. Members of the US-SOT team, especially Drs. T. Tarbell and R. Shine, are also acknowledged for their close cooperation. I’d also like to thank Drs. J. Jurcak and K. Reardon for their close cooperation in the studies of penumbral microjets.

References

  1. Alpert, S.E., Tiwari, S.K., Moore, R.L.: Hi-C Observations of sunspot penumbral bright dots. ApJ 822, 35 (2016)Google Scholar
  2. Borrero, J.M., Ichimoto, K.: Magnetic structure of sunspots. Living Rev. Sol. Phys. 8, 4 (2011)Google Scholar
  3. De Pontieu, B., McIntosh, S.W., Hansteen, V.H., et al.: A tale of two spicules: the impact of spicules on the magnetic chromosphere. PASJ 59, S655–S662 (2007)Google Scholar
  4. Jurcak, J., Katsukawa, Y.: The properties of penumbral microjets inclination. A&A. 488, L33–L36 (2008)Google Scholar
  5. Jurcak, J., Katsukawa, Y.: Temporal downflows in a penumbra. A&A. 524, A21 (2010)Google Scholar
  6. Katsukawa, Y.: Fine structures in a Sunspot revealed by HINODE. Parity 23, 39–43 (2008)Google Scholar
  7. Katsukawa, Y., Jurcak, J.: A new type of small-scale downflow patches in sunspot penumbrae. A&A. 524, A20 (2010)Google Scholar
  8. Katsukawa, Y., Berger, T.E., Ichimoto, K., et al.: Small-scale jetlike features in penumbral chromospheres. Science 318, 1594–1597 (2007)Google Scholar
  9. Katsukawa, Y., Kimura, Y., Okamoto, T.J., Tarbell, T.D.: Rapid evolution of penumbral microjets and their impacts on heating of the outer solar atmosphere. ApJ (2018, submitted)Google Scholar
  10. Magara, T.: A magnetohydrodynamic model focused on the configuration of magnetic field responsible for a solar penumbral microjet. ApJ 715, L40–L43 (2010)Google Scholar
  11. Nakamura, N., Shibata, K., Isobe, H.: Numerical simulation of three-dimensional asymmetric reconnection and application to a physical mechanism of penumbral microjets. ApJ 761, 87 (2012)Google Scholar
  12. Reardon, K., Tritschler, A., Katsukawa, Y.: Spectral signatures of penumbral transients. ApJ 779, 143 (2013)Google Scholar
  13. Samanta, T., Tian, H., Banerjee, D., Schanche, N.: Dynamics of subarcsecond bright dots in the transition tegion above sunspots and their relation to penumbral micro-jets. ApJ 835, 19 (2017)Google Scholar
  14. Shibata, K., Nakamura, T., Matsumoto, T., et al.: Chromospheric anemone jets as evidence of ubiquitous reconnection. Science 318, 1591–1594 (2007)Google Scholar
  15. Solanki, S.: Sunspots: an overview. A&ARv 11, 153–286 (2003)Google Scholar
  16. Tian, H., Kleint, L., Peter, H., et al.: Observations of subarcsecond bright dots in the transition region above sunspots with the interface region imaging spectrograph. ApJ 790, L29 (2014)Google Scholar
  17. Toriumi, S., Katsukawa, Y., Cheung, M.C.M.: Light bridge in a developing active region. I. Observation of light bridge and its dynamic activity phenomena. ApJ 811, 137 (2015a)Google Scholar
  18. Toriumi, S., Cheung, M.C.M., Katsukawa, Y.: Light bridge in a developing active region. II. Numerical simulation of flux emergence and light bridge formation. ApJ 811, 138 (2015b)Google Scholar
  19. Vissers, G.J.M., Rouppe van der Voort, L.H.M., Carlsson, M.: Evidence for a transition region response to penumbral microjets in Sunspots. ApJ 811, L33 (2015)Google Scholar

Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Solar Science ObservatoryNational Astronomical Observatory of JapanMitaka, TokyoJapan

Personalised recommendations

Cite chapter

Buy options