![]() 18 The locations and orientations of the PILs result from interactions between large-scale coronal cells and the Sun’s differential rotation. ![]() Called coronal cells, the magnetic structures form a network of bright centers separated by dark boundaries. The most illuminating observational discovery about filament channels in recent years has been the recognition of a unique pattern of coronal structures that line the two sides of long filaments. Dextral filaments predominate in the northern hemisphere, whereas sinistral filaments predominate in the southern hemisphere. The handedness of filaments displays a remarkable large-scale hemispheric pattern. When the filament is sinistral, the loops skew to the right and when the filament is dextral, the loops skew to the left. From a bird’s-eye view, the loops that make up an arcade line up at an angle relative to the filament that runs below. Interestingly, the coronal loops (blue arcs) have the opposite chirality as the filaments and channels they overlie. Nonetheless, the barbs appear to connect to those minority-polarity patches or perhaps to tiny PILs around them. The origin of filament handedness may be in the presence of weak minority-polarity fields (blue dots) on only one side of the channel. If one imagines the filament spine as a highway with traffic moving in the field direction, the barbs of sinistral filaments bend away like left-handed exits and the barbs of dextral filaments bend away like right-handed exits. The other characteristic filament structures are the barbs that divert filament threads away from the spine and into the chromosphere and photosphere below. However, filaments only form when all the fibrils reflect the chirality of the filament channel. In general, the fibrils may orient in any direction and sometimes form bridges over the PIL. The aptly named chromospheric fibrils (green) are threads of plasma that follow field lines emanating from or converging into areas of concentrated magnetic fields (red or blue circles). Left-pointing channels are classified as sinistral and right-pointing ones dextral. Viewed from the positive polarity side of the PIL, the magnetic fields in the filament channel (white arrows) can point either to the left or to the right. The main upper body of the filament (red), usually called the spine, stretches through the corona above the boundary between two opposite-polarity regions on the photosphere called a polarity inversion line (PIL). 13 As illustrated in the figure, the three chiralities are intimately related. Solar filaments-or prominences, as they’re called when they protrude over the edge of the solar disk-possess handedness or chirality, as do the channels they run through and the coronal-loop arcades overhead. Because Alfvén waves cause no plasma compressions, they can propagate in tenuous plasmas with virtually no energy losses. In addition, they can easily dissipate their burden of energy by forming sonic shocks that radiate strongly and generate heat. SolarMax is Californias premier residential solar energy company, and we can help you and your family convert your home to a more environmentally friendly. They also transport the momentum of their entrained plasma. Magnetic waves transport energy in proportion to the square of their amplitudes and to their propagation speed. ![]() In a nonideal plasma with finite electrical resistance, ion acoustic waves-sound waves that interact with the electromagnetic fields present-and other types of waves are possible. Because they combine longitudinal compression of the plasma and the transverse displacement of the lines of force, they propagate at an angle to the field lines. Magnetosonic waves are hybrids of sound waves and Alfvén waves. Alfvén waves travel at a speed that increases as the local plasma density decreases and as the magnetic field strength increases. The surrounding plasma wiggles along with field lines but it is not compressed as happens with sound waves. Alfvén waves are periodic transverse displacements of the lines of force. They are just sound waves, albeit in a gas of charged particles. Longitudinal plasma-density waves propagate at the local speed of sound in the direction of the field. Three types of waves are possible in an ideal plasma that has zero electrical resistance. The Earth will be farthest from the Sun at this time.When shaken by external forces, a bundle of magnetic field lines and the plasma filling them can develop traveling waves. Dates are based on the Gregorian calendar.Īphelion is on 6 Липень 2023 p. Time is adjusted for DST when applicable. ![]() Business Date to Date (exclude holidays). ![]()
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