Numerical evaluation of statistical acceleration for energetic particles in the interplanetary medium at 2.5 and 5.0 AU

✍ Scribed by X. Moussas; J. J. Quenby; J. F. Valdes-Galicia

• Publisher: Springer
• Year: 1987
• Tongue: English
• Weight: 852 KB
• Volume: 112
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00148791

✦ Synopsis

Numerical integration of particle trajectories is performed to evaluate the statistical acceleration coefficients DTc for 1 to 100 MeV protons in a solar wind corotating interaction region (CIR) seen at 2.5 and 5.0 AU. Acceleration is followed in the solar wind reference frame and is due to random wave-particle interactions and to random drift motion in moderate scale field gradients. Drr due to the first effect reaches a peak value of 4 x 10 7 MeV 2 s -1 post shock at 10 MeV at 2.5 AU consistent with estimates based both upon cyclotron resonance and transit time damping theory. DTr from the second effect is less well established but is of the order of 10-7 MeV 2 s -1 at 10 MeV, 5 AU. A comparison is made between the time constant for statistical acceleration within this CIR and estimates for diffuse shock acceleration and adiabatic deceleration. All three time constants are of the same order, but deceleration is faster than shock acceleration which in turn is faster than statistical acceleration.