Floccules (from Latin floccus - “scrap”; singular number of floccule or floccule [1] ; the term "chromospheric torches" is also used) - fibrous formations in the solar chromosphere , which have a greater brightness and density than the surrounding areas. They are a continuation of photospheric torches into the chromosphere. Usually located near areas with strong magnetic fields (active areas), often surrounded by sunspots .
Areas of the chromosphere occupied by flocculi are called "floccule fields." Sometimes, following the English language literature, in which the term flocculi is considered obsolete, flocculi and floccule fields are called “beaches” ( English plages ). [2]
On ordinary (executed in white light) images of the Sun, flocculi are practically invisible. They are observed in the light of Fraunhofer lines of medium and high intensity on images of the Sun ( spectroheliograms ) specially obtained at the frequencies of these lines, where they are usually visible as bright regions with a size of a few minutes of the arc . Most often, floccules are observed in the light of the hydrogen line Hα and the H and K lines of ionized calcium (CaII). In special cases (in the light of a number of relatively weak metal lines or in the HeI line), on the contrary, they may look like dark areas.
Floccules are oriented along the lines of force of the magnetic field. In the Hα line, they look in a characteristic way, reminiscent of the location of metal filings on glass located above the magnet . Sometimes a vortex structure like a cyclone appears above single sunspots.
The floccules in the H and K CaII lines are larger, located higher than the hydrogen ones, and look much more amorphous. Calcium flocculi are good indicators of the appearance of local magnetic fields on the Sun: they are noticeable wherever the magnetic field exceeds 5 Oe . The floccule brightness increases with field strength (up to fields of several hundred Oe).
The number of floccules on the solar disk varies with solar activity : during the period of the maximum of the solar cycle, the flocculi visible in the Hα line can cover up to one tenth of the solar disk.
Notes
- ↑ gramota.ru
- ↑ Compendium of aeronomy / Edited by E. Rikitake. - Terra Scientific Publishing Company, 1990.
Literature
- Flocculi / M. Livshits // Space Physics: A Small Encyclopedia / Editorial: R. A. Sunyaev (Ch. Ed.) And others - 2nd ed. - M .: Soviet Encyclopedia , 1986. - S. 700. - 783 p. - 70,000 copies.