Coronal loop

The corona is the outer part of the solar atmosphere. Its name derives from the fact that, since it is extremely tenuous with respect to the lower atmosphere, it is visible in the optical band only during the solar eclipses as a faint crown (corona in Latin) around the black moon disk. When inspected through spectroscopy the corona reveals unexpected emission lines, which were first identified as due to a new element (coronium) but which were later ascertained to be due to high excitation states of iron. It became then clear that the corona is made of very high temperature gas, hotter than 1 MK(megakelvin). Almost all the gas is fully ionized there and thus interacts effectively with the ambient magnetic field. It is for this reason that the corona appears so inhomogeneous when observed in the X-ray band, in which plasma at million degrees emits most of its radiation. In particular, the plasma is confined inside magnetic flux tubes which are anchored on both sides to the underlying photosphere. When the confined plasma is heated more than the surroundings, its pressure and density increase. Since the tenuous plasma is optically thin, the intensity of its radiation is proportional to the square of the density, and the tube becomes much brighter than the surrounding ones and looks like a bright closed arch: a coronal loop.
Coronal Loops: Observations and Modeling of Confined Plasma

Credit: Fabio Reale

Coronal loop

The corona is the outer part of the solar atmosphere. Its name derives from the fact that, since it is extremely tenuous with respect to the lower atmosphere, it is visible in the optical band only during the solar eclipses as a faint crown (corona in Latin) around the black moon disk. When inspected through spectroscopy the corona reveals unexpected emission lines, which were first identified as due to a new element (coronium) but which were later ascertained to be due to high excitation states of iron. It became then clear that the corona is made of very high temperature gas, hotter than 1 MK(megakelvin). Almost all the gas is fully ionized there and thus interacts effectively with the ambient magnetic field. It is for this reason that the corona appears so inhomogeneous when observed in the X-ray band, in which plasma at million degrees emits most of its radiation. In particular, the plasma is confined inside magnetic flux tubes which are anchored on both sides to the underlying photosphere. When the confined plasma is heated more than the surroundings, its pressure and density increase. Since the tenuous plasma is optically thin, the intensity of its radiation is proportional to the square of the density, and the tube becomes much brighter than the surrounding ones and looks like a bright closed arch: a coronal loop.

Credit: Fabio Reale


Posted 5 months ago with 1,147 notes
Tagged:coronal loopmagnetic fieldastrophysicsHeliophysicssunphysicsplasmagifspace

  1. lets-fucking-talk-about-space reblogged this from spaceplasma
  2. captmarbles reblogged this from spaceplasma
  3. spaceadmiraldee reblogged this from spaceplasma
  4. teksorbkyva reblogged this from spaceplasma
  5. theskyisfullofghosts reblogged this from physicsshiny
  6. dailyvernacularisms reblogged this from sagansense
  7. snowbunnyfoofoo reblogged this from sagansense
  8. the-passive-aggression-of-christ reblogged this from kevin00101
  9. kevin00101 reblogged this from spaceplasma
  10. jadw reblogged this from spaceplasma
  11. bellafunt reblogged this from spaceplasma
  12. jor-el-of-krypton reblogged this from spaceplasma
  13. hallsoferiador reblogged this from spaceplasma
  14. danielmartinsposts reblogged this from spaceplasma
  15. xxnthnxx reblogged this from spaceplasma
  16. quantum-leaps-of-logic reblogged this from spaceplasma
  17. techno-gal reblogged this from nizdawg
  18. lady-danute-titania-mormont reblogged this from deepspaceobjects and added:
    foe
  19. nizdawg reblogged this from sagansense
  20. angry-teenager reblogged this from tuggywuggy
  21. elliesurf98 reblogged this from accio-smerch
  22. accio-smerch reblogged this from fuckyeah-space
  23. omniwitch reblogged this from sablepuss
  24. staylucidkid reblogged this from megacosms
  25. moshsquats reblogged this from spaceplasma
  26. sablepuss reblogged this from troll-bridge
  27. troll-bridge reblogged this from megacosms