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 fully 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 automatic transmission lines and pipelines, and even human health.

The scientific interest due to the possibility of studying in space collisionless hot plasma, which is very difficult to recreate in the laboratory, in particular, to evaluate the properties of the propagation of radio waves in it, the development of a variety of plasma instabilities, etc.

For the continuation and development of this research on neglected 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 distant cosmic objects — black holes, Supergalaxy, clouds of dark matter, etc. — With an interferometer with a very large base. However, in parallel with the main experiment on this spacecraft was a place for instrument complex "Plasma-F", whose responsibilities include direct measurements in interplanetary space of two important components of the solar radiation — the solar wind plasma flows and fluxes of energetic particles from the Sun. The orbit of the satellite vysokoapogeynogo "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, limited towards the Earth magnetopause (the distance to it in sunflower sector is about 60 thousand km), in the direction of the Sun — Earth shock (distance to which the Earth is about 100 million km). Inside the magnetosphere, interplanetary medium almost does not penetrate, so to study it necessary to go beyond low-Earth shock wave.

Due to its high apogee (360 million km), a long period of treatment (8.5 days) and relatively low perigee (5-10 thousand km) satellite "Spektr-R" is about 6-8 days is in the undisturbed interplanetary medium, and then quickly passes through almost all regions of the magnetosphere, registering their condition.

One of the important components of the interplanetary space and magnetospheric plasma is the so-called "energetic" component — ions (mostly protons) and electrons with energies much higher than the average ("Heat"), the bulk of the energy of the plasma. Such particles include, for example, solar cosmic rays or particle radiation belts. In addition to actually study the properties of near-Earth space, speed up the research process and the formation of energetic plasma are 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 implementation of such a dedicated experiment to study the fine structure of the acceleration processes.

The scientific payload "Plasma-F" includes a display of energetic particles MEP, energospektrometr plasma BCSM, MMFF magnetometer, a system for collecting scientific information SSNI-2. Instruments were included after 05.08.2011 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. BCSM appliance 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 ion temperature and concentration, and with a resolution of 0.03 in magnitude and direction of the vector flow of solar wind ions. The device registers the MEP 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 about the fine structure of the solar wind and the fluxes of energetic particles continues to flow and be processed. As an example, Figures 1 and 2 show fast and large variations quasiharmonic magnitude and direction of flow of the ions in the shock wave front interplanetary measured October 24, 2011 with a resolution of 30 ms. It is evident that a large (approximately 4 times) the density jump solar wind flow occurs in such a short time as 0.3, and the density variations and the polar angle of flow have a period of about 0.5 seconds. Measurements showed the 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 interplanetary plasma still has not yet been received.



 Figure 1. Dependence of ion flux from the solar wind crossing time 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 centimeter per second, multiplied by 10 to the 9th degree.



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


The orbit of the satellite "Spektr-R" in August 2011



The figure shows an example of typical results from the instrumental record of 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 of the satellite orbit have been a very intense variations of electron fluxes (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 of 22.10.2011, the — the flow of solar wind ions according to the device BCSM and flux of energetic electrons (50-300 keV), according to the MEP unit. It can be seen that the main disturbance of the flow of ions, which has very sharp edges, comes to satellite 25.10.2011, and the flow of energetic electrons begins his rise two days before the perturbation of the plasma. The flux of energetic particles, mainly changing very slowly, but increases by more than an order of magnitude compared to the background, while the ion flux increases only twice.



In the "A" is an example of such monitoring — recording changes in the density of solar wind (red line) during 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 instrument record BCSM temporal resolution of plasma parameters (0.03 s) allows us to observe previously inaccessible phenomena. In the "B" is shown (see red lines and dots) example of very fast variations of the density of the solar wind in the event of 25.10.2011 with the 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. This panel shows the (blue line) the results of simultaneous measurements with a resolution of 3 on the U.S. spacecraft WIND — the fastest of the data available in addition to our own. It is evident that these measurements up to 100 times slower than ours, do not give real information about the variability of plasma parameters.




The high temporal and energy resolution of the instrument BCSM revealed rapid variations of the relative content of helium ions (alpha particles) in the solar wind, which is important for understanding the processes in the solar corona, which is the source of disturbances coming from the Sun to the Earth.

Of energy spectrograms of solar wind (fig. A) shows that the device can reliably and accurately separate the helium ions (blue and blue stripe) from protons (red-yellow-green stripe). The resulting time variation of helium content (see Fig. B) shows that in contrast to the conventional view the content can experience fast and large variations in the second range (e.g., decrease from 6% to 4% in total 3), indicating that of small-scale heterogeneous layering strong solar corona.



BCSM device data with a very high time resolution allow us to construct a frequency range of variations of the solar wind ions over a wide frequency range of 4 * 10/02/15 Hz (sm.panel "A"). This allows you to get a first experimental confirmation of the hypotheses on the parameters of the plasma jet of the multiscale nature of the solar wind. As can be seen from the figure, we observe the simultaneous existence in the solar wind as the big jets with the frequency variations of 0.1-1 Hz and smaller jets with a frequency in the range 1-15 Hz.



 This "struynost" reflects, obviously, complex multifractal nature of the sources of solar wind in the solar corona, considered theoretically and shown in the diagram panel "B".


Given the very positive experience of the devices BCSM and MEP in the experiment "Plasma-F" on the spacecraft "Spektr-R" (with an apogee of 360 thousand kilometers), it seems appropriate to establish a similar experiment on the spacecraft "Spektr-RG", is sent to the back of the libration point L2 (a distance okolo1.5 million miles) in order to be able to:

a) monitor the state of the environment in the vicinity of the spacecraft;
b) to examine the dynamics by direct measurement of plasma and energetic particles in the interplanetary medium scale of about 2 million square kilometers;
a) to investigate the movement and disturbance of the Earth’s magnetosphere long tail, which, among other things, may also affect the processes in the near-Earth space. 




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