![]() It is well-accepted that plasma bubbles are generated via the Rayleigh–Taylor instability that occurs at the magnetic equator after sunset when the eastward electric fields increase. ![]() ( 1982) showed that FAIs observed using the ALTAIR radar were collocated with plasma depletions measured using the Atmosphere Explorer-E satellite. The FAI echoes are considered to be manifestations of plasma bubbles (e.g., Woodman and LaHoz 1976). Intense backscatter echoes caused by Bragg scattering from field-aligned irregularities (FAI) with spatial scales of one half of the radar wavelength have been observed with VHF, UHF, and L-band radars (e.g., Woodman and LaHoz 1976 Tsunoda 1980a, b). Within plasma bubbles, various size scales of plasma density irregularities exist. Plasma bubbles, which are localized plasma density depletions in the ionosphere at equatorial and low-latitude regions, have been studied since their discovery by Booker and Wells ( 1938) with various radio and optical techniques (see reviews by Hysell 2000 Makela 2006 Kelley et al. The other candidate is the uplift of the F layer by the meridional neutral winds in the thermosphere, which may be associated with midnight temperature maximums in the thermosphere. One candidate is the seeding of the Rayleigh–Taylor instability by atmospheric gravity waves propagating from below into the ionosphere. The mechanisms for generating the post-midnight irregularities are still unknown, but two candidates have been proposed. ![]() However, recent observations during a solar minimum period show a high occurrence rate of irregularities post-midnight around the June solstice. Plasma bubbles are well-known to frequently occur post-sunset when the solar terminator is nearly parallel to the geomagnetic field lines (during equinoxes at the longitude where the declination of the geomagnetic field is almost equal to zero and near the December solstice at the longitude where the declination is tilted westward), especially during high solar activity conditions via the Rayleigh–Taylor instability. Ionospheric irregularities can occur in equatorial plasma bubbles. We will let you know if we have to and if supplier is out we will refund you.This paper provides a brief review of ionospheric irregularities that occur in magnetically equatorial and low-latitude regions post-midnight during low solar activity periods. Pelleted seeds make these much easier to plant because they have a coating on them that way you can see to plant the seeds.Many of these seeds we have in stock if you are buying a larger mount we may have to get it from supplier. This is for 250 thru 1,000 pelleted seeds you pick the amount you need. These should be just pressed in the soil they need light to germinate. These are best to start indoors in a cell tray or seed flat using a propagation dome. They have a well branched growing habit that have a high quality look. This petunia will get 10" to 12" tall and spread about 10" to 15" the flowers are large about 3" across. The Dreams petunia will bloom in early spring to late summer months. The Dreams series has many colors to pick from colors are bright and vivid. The Petunia Dreams series is a great variety of upright petunia that does well in planter and larger pots. Petunia Seeds Petunia Dreams Midnight 250 thru 1,000 Pelleted Seeds
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