Полярные геомагнитные возмущения и связанные с ними явления : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая 1986 г., Суздаль / Междунар. геодез. и геофиз. союз, междунар. ассоциация геомагнетизма и аэрономии, АН СССР, КНЦ, ПГИ. – Апатиты : [б. и.], 1989.

R E F E R E N C E S 1 . STORMER С. The p o la r a u ro r a . - O x fo rd , C larendon P r e s s , 1955. 2. NADUBOVITCH Y u .A ., STARKOV G .V . F ib ro u s s tr u c tu r e o f weak uniform a r c s o f a u r o r a s . - Geomagnetism and Aeronomy, 1962, v . 2 , p . 7 1 -7 3 . 3 . OGUTI T . Metamorphoses o f A u ro ra. - Memoirs o f n a tio n a l I n s t i t u t e o f P o la r R e sea rch , S e r ie s A, 19 7 5, No 12 , 100 p. 4 . NAZARCHUCK G .K . A d r i f t Inh om o g en eities i n the a u ro ra e t r a i t e d band. - Subm itted to Plasma I n s t a b i l i t i e s Symp., XVI IUGG/IAGA G en eral Assem bly, G ren o b le, F ra n ce , 19 7 5 . 5 . DAVIS T.N . Observed c h a r a c t e r i s t ic s o f au ro ra fo rm s. - Space S c i.R e v ., 1978 , v .2 2 , No 1 , p . 7 7 - 1 1 1 . 6 . SWIFT D.W, Mechanisms f o r a u r o r a l p r e c i p i t a t i o n : A r e v ie w . - Rev. G eophys.Space P h y s ., 19 8 1, v . 9 , No 1 , p . 1 8 5 - 2 1 1 . 7 . SCARF F .L ., FREDERIKS R .W ., RUSSELL C .T . C u rr e n t-d riv e n plasma i n s t a b i l i t i e s a t h ig h l a t i t u d e s . - J .G e o p h y s .R e s ., 1975» v .8 0 , No 1 6 , p . 2030- 2040. K .D .Danov, M .B .K a rta le v A POSSIBLE MECHANISM OF IONOSPHERIC IONIZATION DENSITY VARIATIONS CAUSED BY SUDDEN COMMENCEMENT The idea to generalize the theory of surface solitary wa v e s to the case of stratified gas ai m i n g further a p p l ication to the case of two-layer upper atmosphere model has b e e n re c e n t l y exploited. Thome (1968) developed a theory of long-period surface wa v e s propagating on the b o undary between two isoter- m al infinite layers an d rea c h e d quite a go o d agreement w i t h the experiment. D a n o v et al. (1982) pro p o s e d a theory of solitary waves propagating along a separating surface of two gas layers w i t h a finite depth. The r e s t r i c t i o n for constant temperature of u n d i sturbed flows h o w e v e r remained. I n spite of some a greement w i t h experiments (in the wave speed fo r instance) this ap p r o a c h is inconvenient for treating such a pro b l e m as solving the i o n density equations u n d e r real conditions i n order to ob t a i n the variations of electron density. A very successful aproach, capable to do this, is done in the study of R i chmo n d an d M a t sushita (1975) wh e r e the hydrodynamic equation are solved nume r i c a l l y b y stepping towards i n time over a two-dimensional gr i d of points i n latitude be t w e e n the pole an d the equator. The obtained i n this wave g ravity wave response to the polar source is u s e d by Roble et al.(1978) to calculate the ionos pheric properties of a concrete disturbance (September 18, 1974 Sud d e n Commencement) as we l l as to compare w i t h measurements over M i l l stone Hill, M a s s a c husetts (42.6 N, 71.5 W) a n d Arecibo, Puerto Rico (18.3 N, 66.7 W). H ere w e are c a l c ulating the travelling n eutral disturbance and the time v a r iations of e l ectron density us i n g the con d itions of the above m e n tioned 95