Anomalously low proton temperatures in the solar wind following interplanetary shock waves—evidence for magnetic bottles?

Occasionally, anomalously low values of the solar wind proton temperature Tp are observed when the solar wind velocity υ is high. A large fraction of such measurements by the Vela 3 satellites follow the passage of interplanetary shocks by some 20–60 hours. Of 24 postshock events in which υ exceeded 400 km sec−1 and for which Vela 3 measurements are available, 12 exhibited plasma states of anomalously low Tp, high υ. The proton density at the time of these observations typically was depressed below normal, and the velocity tended to be constant or falling. A very strong association with abnormally high (≥15%) concentrations of He++/H+ in the solar wind is noted for these anomalous proton temperatures, the usual temporal sequence of events at 1 AU being: (1) shock wave, (2) helium enrichment, and (3) low Tp, high υ. It is suggested that these observations are consistent with a model for some shock wave disturbances that includes the ejection of new material (distinguished by the helium enrichment at 1 AU) into the solar wind at the time of large solar flares and the formation of a magnetic bottle configuration in the solar wind behind and within the ejecta. The anomalously low proton temperatures then result from the adiabatic cooling of the plasma within the magnetic bottle.

[1]  A. Hundhausen.  Nonthermal heating in the quiet solar wind , 1969 .

[2]  J. Asbridge.  Compressions and Rarefactions in the Solar Wind' Vela 3 J. T. GosLInG, A. J. HUN)HAUSEN, AND V. Pzzo , 1972 .

[3]  A. Hundhausen.  Nonlinear model of high‐speed solar wind streams , 1973 .

[4]  A. Hundhausen.  Flare-Produced Interplanetary Shock Waves , 1972 .

[5]  S. Sydoriak,et al.  SOLAR-WIND PROTON PROPERTIES: VELA 3 OBSERVATIONS FROM JULY 1965 TO JUNE 1967. , 1970 .

[6]  L. Burlaga,et al.  Hydromagnetic shocks in the solar wind , 1969 .

[7]  A. Hundhausen,et al.  Vela Satellite Observations of Solar Wind Ions , 1967 .

[8]  A. Hundhausen.  Composition and dynamics of the solar wind plasma , 1970 .

[9]  R. Hartle,et al.  Nonthermal heating in the two‐fluid solar wind model , 1970 .

[10]  A. Hundhausen,et al.  Large‐scale characteristics of flare‐associated solar wind disturbances , 1970 .

[11]  J. Asbridge,et al.  The helium-enriched interplanetary plasma from the proton flares of August/September, 1966 , 1971 .

[12]  A. Hundhausen,et al.  Satellite observations of interplanetary shock waves , 1968 .

[13]  A. Lazarus,et al.  Observations of the interplanetary plasma subsequent to the 7 July 1966 proton flare. , 1969 .

[14]  A. Hundhausen,et al.  Discontinuities in the solar wind associated with sudden geomagnetic impulses and storm commencements , 1967 .

[15]  T. D. Wilkerson,et al.  Plasma observations on Explorer 34 , 1968 .

[16]  H. E. Taylor.  Sudden commencement associated discontinuities in the interplanetary magnetic field observed by IMP 3 , 1969 .

[17]  L. Burlaga,et al.  Causes of sudden commencements and sudden impulses. , 1969 .

[18]  L. Burlaga,et al.  Energy transfer at colliding streams in the solar wind , 1971 .

[19]  S. Bame,et al.  Solar flares and solar wind helium enrichments: July 1965–July 1967 , 1972 .

[20]  T. Gold.  ENERGETIC PARTICLE FLUXES IN THE SOLAR SYSTEM AND NEAR THE EARTH , 1960 .

[21]  L. Burlaga,et al.  The heating of the solar wind , 1970 .

[22]  A. Hundhausen.  Interplanetary shock waves and the structure of solar wind disturbances , 1972 .

[23]  R. W. Fredricks.  Electrostatic heating of solar wind ions beyond 0.1 AU , 1969 .

[24]  A. Hundhausen,et al.  SOLAR WIND ELECTRONS: VELA 4 MEASUREMENTS. , 1968 .

[25]  P. Sturrock,et al.  Two-Fluid Model of the Solar Wind , 1968 .

[26]  A. Hundhausen,et al.  Measurements of Proton Temperatures in the Solar Wind , 1966 .

[27]  J. Chao.  Interplanetary collisionless shock waves. , 1970 .

[28]  A. Hundhausen,et al.  Observation of a solar flare induced interplanetary shock and helium-enriched driver gas , 1970 .