A white or milky and opaque granular deposit of ice formed by the rapid freezing of supercooled water drops as they impinge upon an exposed object. It is denser and harder than hoarfrost, but lighter,
softer, and less transparent than glaze. Rime is composed essentially of discrete ice granules and has densities as low as 0.2-0.3 g cm-3. Glaze is generally continuous but with some air pockets and has much higher densities. Factors that favor rime formation are small drop size, slow accretion, a high degree of supercooling, and rapid dissipation of latent heat of fusion. The opposite effects favor glaze formation. Both rime and glaze occur when supercooled water drops strike an object at a temperature below freezing. Such formation on terrestrial objects constitutes an ice storm; on aircraft, it is called aircraft icing (where rime is known as rime ice). Either rime or glaze may form on snow crystals, droxtals, or other ice particles in the atmosphere. When such a deposit is wholly or chiefly of rime, snow pellets result; when most or all of the deposit is glaze, ordinary hail or ice pellets result. The alternating clear and opaque layers of some hailstones represent glaze and rime, deposited under varying conditions around the growing hailstone.
Deposit of ice generally formed by the freezing of supercooled fog or cloud droplets on objects the surface temperature of which is below or slightly above 0 degrees C.
An opaque coating of tiny, white, granular ice particles caused by the rapid freezing of supercooled water droplets on impact with an object. See also clear ice.
Same as rime, but especially applied to rime formation on aircraft. Flight through an extremely supercooled cloud (-10C or colder) is very conducive to rime icing. This type of ice weighs less than cl
ear ice, but it may seriously distort airfoil shape and thereby diminish the lift. In aviation parlance, ice that has the ideal rime character may be called kernel ice, and that intermediate between rime and clear ice may be called milky ice.
A simple, cooled cylindrical rod, usually of metal or glass, that is exposed to the airflow in a cloud to collect supercooled cloud droplets for chemical analysis. The collection efficiency of the rod
, which is dependent on the size of the drops, can be calculated.
In the magnetosphere, a region of current that flows from east to west in a disk-shaped region near the geomagnetic equator in the outer of the Van Allen radiation belts. The current is produced by th
e gradient and curvature drift of the trapped charged particles. The ring current is greatly augmented during magnetic storms because of the hot plasma injected from the magnetotail. This increase in the ring current causes a worldwide depression of the horizontal geomagnetic field during a magnetic storm.
One of the major current systems confinedwithin planetary magnetospheres. The ring current circles in the magneticequatorial plane of magnetospheres. It is generated by the longitudinaldrift of energe
tic charged particles trapped on inner, dipole-likemagnetospheric field lines. At the Earth, the ring current is carried by 10to 200 keV charged particles typically located at L-shells between 3 and 6.The ring current is also the primary driver of the Sym H and Dst Indices ofmagnetic storm activity at the Earth.
A galaxy with a ring-like appearance around the central luminous center. The ring consists of massive, relatively young bright stars. It is believed that ring galaxies result from the head-on collisio
n of two different galaxies.