IPS OBSERVATIONS OF FLARE-GENERATED INTERPLANETARY SHOCK WAVES DURING THE SECOND STIP INTERVAL (MARCH 15-MAY 15, 1976)

Dynamical characteristics for interplanetary shock waves are investigated from observations using solar, IPS and geomagnetic data during the second STIP interval (March - May 1976). In the case of the shock wave generated by the solar flare at 08 UT on March 23, 1976, the shock velocity, Vs, is seen to be proportional to the heliocentric distance, R, as follows: Vs ∞ R^-0.4, which suggests a blast-like deceleration. The trajectory for the shock wave generated by the solar flare at 21 UT on April 30, 1976 indicates a piston-driven character to about 0.4 AU. In the cource of further expansion, this shock wave was strongly decelerated. The shock velocity is expresses by a formula: Vs ∞ R^-0.8 (R≿0.4 AU), which suggests a strong deceleration of the piston.