Spacecraft radio scattering observations of the power spectrum of electron density fluctuations in the solar wind
Spacecraft radio scattering observations of the power spectrum of electron density fluctuations in the solar wind
复制标题
DOI：
10.1029/ja084ia12p07288
复制
发表时间：
1979-12
影响因子：
--
通讯作者：
R. Woo;J. Armstrong
中科院分区：
文献类型：
--
作者：
R. Woo;J. Armstrong
根据维京海盗、Helios和Pioneer航天器的相位振荡和谱展宽观测结果，推断了太阳赤道区的太阳风电子密度功率谱。覆盖的日心距离范围为2- 215 R/sub S/，并且对于靠近太阳的一些观测，光谱延伸到高达100 Hz的波动频率。对于日心距离>或近似。=20 R/sub S/等效航天器测量的一维密度谱V/sub n/e在频率范围10/sup-4/-5 x 10/sup-2/ Hz内可通过单次幂律（f/sup -alpha/）很好地建模。平均光谱指数。阿尔法帽。是1.65，非常接近Kolmogorov值的5/3。在太阳风速不变的假设下，V/sub n/e的变化规律为R/sup-3.45/，其中R为日心距。在20 R/sub S/内，V/sub n/e在10/sup-3/-10/sup 1/ Hz的频率范围内仍可用单一幂律来模拟，但谱指数变小，阿尔法帽。约1.1。20 R/sub S/的密度谱的平坦化可能与太阳附近区域的能量沉积和太阳风的加速有关。
Solar wind electron density power spectra in the solar equatorial region are inferred from observations of phase scintillations and spectral broadening made with the Viking, Helios, and Pioneer spacecraft. The heliocentric distance range covered is 2--215 R/sub S/, and for some observations close to the sun the spectra extend to fluctuation frequencies as high as 100 Hz. For heliocentric distances > or approx. =20 R/sub S/ the equivalent spacecraft-measured one-dimensional density spectrym V/sub n/e is well modeled by a single power law (f/sup -alpha/) in the frequency range 10/sup -4/-5 x 10/sup -2/ Hz. The mean spectral index ..cap alpha.. is 1.65, very close to the Kolmogorov value of 5/3. Under the assumption of constant solar wind speed, V/sub n/e varies as R/sup -3.45/, where R is heliocentric distance. Within 20 R/sub S/, V/sub n/e can still be modeled by a single power law over the frequency range 10/sup -3/-10/sup 1/ Hz, but the spectral index becomes smaller, ..cap alpha..approx.1.1. The flattening of the density spectrum with 20 R/sub S/ is presumably associated with energy deposition in the near-sun region and acceleration of the solar wind.