Experiment "Plasma-F"


Although it is still early humans knew that the sun - the source of all life on Earth, but there are still many invisible threads that bind our star and the Earth, not only is not fully understood, but not even completely investigated. Therefore the study of the diversity of solar-terrestrial relations is of great practical and scientific importance. Pragmatic interest is, first of all, that side of their interaction, which is the general name of "space weather."
It is the constant influence of disturbances coming from the Sun to the Earth space: the generation of magnetic and ionospheric storms, in turn, cause problems in modern engineering systems, radio failure (especially in the polar regions), damage automation power lines and pipelines, and even human health.
The scientific interest due to the possibility of studying in space collisionless plasmas, which is very difficult to recreate in the laboratory, in particular, to assess the features of the propagation of radio waves in it, the development of a variety of plasma instabilities, etc.
To continue and develop this research to running July 18, 2011 the Russian astrophysical satellite "Spektr-R" an experiment "Plasma-F".
The main purpose of the satellite "Spektr-R" - a detailed study of the radio emission deep space objects - black holes, Supergalaxy, clouds of dark matter, etc. - By means of an interferometer with a very large base. However, in parallel with the main experiment, this spacecraft was a place for component complex "Plasma-F", whose task is to direct measurements in interplanetary space, two important components of solar radiation - the solar wind flow and the flow of energetic particles from the Sun. Vysokoapogeynogo orbit satellite "Spektr-R" is a perfect option for this experiment. As you know, the interplanetary medium, interacting with the Earth's magnetic field, creating a huge void - the Earth's magnetosphere, bounded towards the Earth magnetopause (the distance to it in sunflower sector is about 60 sq km), in the direction of the Sun - Earth shock (distance to which the Earth is about 100 sq km). Interplanetary medium into the magnetosphere almost does not penetrate, so to study it necessary to go beyond low-Earth shock wave.
Due to its high apogee (360 sq km), the long period (8.5 days) and relatively low perigee (5.10 sq km) satellite "Spektr-R" about 6-8 days is in the undisturbed interplanetary medium, and then quickly runs through almost all the regions of the magnetosphere, recording their condition.
An important component of the interplanetary space and magnetospheric plasma is the so-called "energetic" component - ions (mostly protons) and electrons with energies much higher than average ("heat") energy of the bulk plasma. These particles include, for example, solar cosmic rays or particle radiation belts. In addition to actually study the properties of near-Earth space, the study of the formation and acceleration of energetic plasma is extremely important for astrophysics. Similar processes (only with higher energies) are responsible for the acceleration of the plasma in astrophysical objects, the properties of which we can be judged only by the properties of the secondary radiation reaching the earth.
In Soviet and Russian space projects gained great experience in such cases. Satellite "Spektr-R" has become a convenient platform for the realization of a specialized kind of experiment to study the fine structure of the acceleration processes.
Scientific equipment "Plasma-F" includes display of energetic particles MEP, energospektrometr plasma BMSV, magnetometer MMFF, scientific data collection system SSNI-2. Instruments were included after 5/8/2011, and since then (with the exception of the device MMFF) is continuously working on the orbit, producing a qualitatively new scientific information from a record high temporal resolution. BMSV device allows you to define the basic parameters of the solar wind and the Earth's magnetosheath with a time resolution of 1.5-3 on a drive speed of the ion temperature and concentration, and a resolution of 0.03 s for the magnitude and direction of the flow of solar wind ions. MEP device registers the energy spectra of the fluxes of energetic ions (in the range of 0.02-1.0 MeV) and electrons (in the range 20-200 keV) with a time resolution better than 1 sec. and with high energy resolution.
Unique information on the fine structure of the solar wind and energetic particle fluxes continues to flow and processed. As an example, in Figure 1 and Figure 2 shows the rapid and large quasi-harmonic variation magnitude and direction of the ion flux at the front of the interplanetary shock wave measured 24 October 2011 with a resolution of 30 ms. It is evident that large (about 4 times) the density jump of the solar wind is in such a short time as 0.3 seconds, and the fluctuations of the density and the polar angle of the flow have a period of about 0.5 seconds. Measurements indicate excitation oscillator (layered) structure of the plasma, standing in relation to the shock front, but running from the sun at a speed of about 500 km / s. Similar data on the interplanetary plasma is still no one has been received.

Fig.1. The dependence of the flux density of solar wind ions with time at the intersection of the interplanetary shock wave propagating in the interval of 10 seconds. World time UT is given in hours, minutes and seconds. The value of the ion flux is expressed in conventional units - the number of particles per square cm per second, times 10 to the 9th degree.

Fig.2. Variations of the deflection angle of the solar wind to the direction of the Sun-Earth on interplanetary shock wave - the top line with the scale on the left, in degrees - in comparison with the variations of the flux - the bottom line with the scale on the right in relative terms. Time in intervals of 4 overlap with Figure 1, shown in hours, minutes, seconds, relative to a conventional origin. The dots on the lines marked by the individual measurements, carried out every 30 ms.

Satellite orbit "Spektr-R" in August 2011

The figure shows an example of typical results from the instrumental record IEP radiation environment around the moon "Spektr-R" border crossing Earth's magnetosphere - Earth shock and the magnetopause. At these boundaries twice on each orbit the satellite's orbit has been a very intense electron flux variations (in the range 30-400 keV) - A panel, and ions (in the range 30-700) - Panel B.

The figure shows an example of the results of registration rather strong interplanetary disturbances from the solar flare was 22/10/2011 - flow of solar wind ions according to the device and BMSV flux of energetic electrons (50 - 300 keV), according to the device MEP. It can be seen that the main perturbation of ions with very sharp edges, comes to satellite 25.10.2011, and the flux of energetic electrons begins its rise two days before the plasma disturbances. The flux of energetic particles, mostly varies rather smoothly, but increases by more than an order of magnitude compared to the background, while the flow of ions increases only twice.

In the "A" is an example of such monitoring - recording changes solar wind density (red line) in a fairly rare event - a very large increase in the density of 14 August 2011 on the same panel as shown by the blue line of the same parameter values ​​according to the U.S. spacecraft WIND . It can be seen that the correspondence of the two satellites is very good.
Achieved in the device BMSV record time resolution of the plasma parameters (0.03 s) allows us to observe previously inaccessible phenomena. In the "B" is shown (see the red lines and dots) example of very rapid variations in the solar wind density event 25.10.2011, with characteristic times of changes in the subsecond range, which is important for understanding the dynamics of the solar wind and its interaction with the Earth's magnetosphere. On the same panel shows (blue line), the results of simultaneous measurements with a resolution of 3 from the U.S. spacecraft WIND - the fastest of the data available in addition to our own. It is seen that these measurements, 100 times slower than ours, do not give the real information about the variability of plasma parameters.

The high temporal and energy resolution of the instrument BMSV revealed rapid variations of relative abundance of helium ions (alpha particles) in the solar wind, which is important for the understanding of the solar corona, which is the source of disturbances coming from the Sun to the Earth.
Spectrogram of energy solar wind (Fig. A) that the device can reliably and accurately separate the helium ions (blue-blue strip) of protons (red-yellow-green stripe). The resulting time evolution of the helium content (see Fig. B) shows that, in contrast to the conventional view this content may experience rapid and large variations in the second range (for example, a decline from 6% to 4% in just 3), indicating that of small-scale heterogeneous layering strong solar corona.

Device data BMSV with very high time resolution allow us to construct the frequency spectrum variations in the flux of solar wind ions in a wide frequency range of 4 * 10/02/15 Hz (sm.panel "A"). This makes it possible for the first time to obtain experimental evidence for the hypothesis that the parameters of the plasma jet nature of multiscale flow of the solar wind. As can be seen from the figure, we see the coexistence of the solar wind streams with a large frequency variations 0.1-1 Hz and smaller jets with a frequency in the range 1-15 Hz.

Such "struynost" reflects, obviously, complex multifractal nature of the sources of solar wind in the solar corona, considered theoretically and shown in panel diagram "B".
Given the very positive experience of the devices BMSV and MEP in the experiment "Plasma-F" on SC "Spektr-R" (with an apogee of 360 km of) it seems appropriate to establish a similar experiment of "Spektr-RG" is sent to the back of the libration point L2 (a distance okolo1.5 million km) in order to be able to:
a) monitor the environment in the vicinity of the spacecraft, and b) to study by direct measurement of the dynamics of the plasma and energetic particles in the interplanetary medium scale of about 2 million km, and c) to investigate the movement and disturbance distant Earth's magnetotail, which, among other things, may implications on the processes in the near-Earth space.