The main results


1949 – 1950


Дипломная работа, выполненная в Харьковском Физико-Техническом Институте.
Determination of effective sections loss of electrons due to charge exchange of Li and Na ions in the energy range 80 - 220 keV. Formation of multiply charged ions at singly charged ions passing through the gas is shown. For the first time the cross sections of multiply charged ions creation due to charge exchange is measured. At 250 keV σ(Na+ → Na+++++) ~ 10-20 cm-2; σ(Li+ → Li++) = 5.5 10-17 cm-2.

Корсунский М. И., Левиант Е. Л., Подгорный И. М., Пивоваров Л. И. Определение эффективных поперечников потери электронов ионами Li и Na в диапазоне энергий 80-220 кэВ. 103, 403 – 405 (1955).

В диапазоне энергии 80 – 220 кэВ измерены сечения перезарядки. Впервые проведены измерения сечений образования многозарядных ионов за счет перезарядки.


1956

Plasma column in a powerful pulse discharge at the rate of current increasing about 1011 A/s is compressed by its own magnetic field (pinch effect). The compression velocity exceeds 2×107 cm/c. The Lorenz electric field V×B/c at the discharge axis reaches 3000 V/cm. The ions of deuterium accelerated along discharge axis causes the D + D nuclear reactions with neutron radiation. Plasma density at the axis of the discharge reaches value 1017 cm-3. The X-ray with energy order of 300 keV is produced by accelerated electrons. The accelerator mechanism at so high plasma density apparently is initiated due to the development of the sausage instability, where strong electric field permits to start particle acceleration.


1956


Railgun (Рельсотрон)

The work was directed for injection of hot plasma in magnetic traps, where plasma confinement can supply thermonuclear reactions D + D and D + T. For producing such experiments the cusped magnetic field trap was developed. The first plasma accelerator and the pinch effect device for neutrons production in powerful discharge were demonstrated in Second Geneva Conference for peaceful use of nuclear energy in 1958 y. Now plasma accelerator is used as a propeller for spacecrafts.

The idea of electrodynamical acceleration (railgun or relsontron) is now used in USA, Japan and Russia for creation of a new type of gun. The several gram projectile gains velocity ~ 10 km/s.


1960


Podgornyi I. M., Sumarokov V. N. The injection of plasmoids into a magnetic trap with a field which increases towards the periphery. J. Nucl. Energy, Part C. – Plasma Phys. 1, 236 (1960).
The work is directed to investigate the possibility of hot plasma confinement in the magnetic field for nuclear fusion production.
It is shown the possibility of hot plasma cloud to capture in a cusped magnetic trap. The stable confinement of plasma injected in the cusped magnetic trap has been demonstrated.

1976

Laboratory experiments with artificial solar wind. I. M. Podgorny.Simulation studies of Space. Fundamentals of Cosmic Phys. 4. 1-72 (1978).

It is shown that the Earth magnetic tail is created at any direction of interplanetary magnetic field. The tail current sheet is not a neutral one. The normal magnetic field component in the tail plays the important role. It is shown that fast particles are penetrated in the magnetosphere via magnetic tail. These particles create the radiation belt.


1979

The magnetic cometary tail was predicted by Biermann and its creation was demonstrated in laboratory simulation.


In 1986 y. the Cometary Explorer spacecraft confirms these results of the laboratory simulation.
The induced magnetosphere with the magnetic tail exists also in Venus. The main characteristic of Venus magnetosphere has been revealed at comparison space measurements and laboratory simulation.
Долгинов Ш. Ш., Дубинин Э. В., Ерошенко Е. Г., Израилевич П. Л., Подгорный И. М. Школьникова С. И. О конфигурации поля в магнитном шлейфе Венеры. Космические исследования. 19, 624-633 (1981).

The electrons are accelerated in the upward field-aligned currents. The electrons with the energy ~10 keV precipitate in the atmosphere and produce aurora.
The Hall earthward electric field is demonstrated in laboratory simulation of the Earth magnetosphere by Minami S., A.I. Podgorny, I.M. Podgorny.( Geophys. Res. Letts. 20, 9-12 (1993)).


1992

Solar flare model

A.I. Podgorny, I. M. Podgotny. Solar Phisics 139, 125 (1992).

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PERESVET code was developed for numerical solving the full system of 3D MHD equations with all dissipative terms. The 3D MHD numerical simulations show that the accumulation of energy for a solar flare occurs in the magnetic field of the current sheet, which is formed at floating of a new magnetic flux in the active region. The mechanism of current sheet creation is demonstrated by the results of numerical simulations using the real preflare state as initial and boundary conditions. For setting the initial and boundary conditions SOHO MDI magnetic maps are used.

In MHD simulation initial and boundary conditions are set from photospheric preflare measurements. No assumption is introduced about the mechanism of solar flare appearance. The current sheet is created above active region due to new magnetic flux if flowing up from an active region. Fast energy release occurs due to magnetic reconnection. The source of thermal X-ray is observed in corona. Electrons accelerated in field-aligned currents hit solar surface and produce high energy power spectrum.


2000

A.I. Podgorny1 and I.M. Podgorny The mechanism of X-rays bright points appearance Astronomy Reports 44, 407-413, (2000)

The mechanism X-ray bright point production is simulated in the numerical MHD experiment. The anisotropy of plasma thermal conductivity in the magnetic field is taken into account. It is shown that plasma heating can be produced by slow magnetic line reconnection around the neutral line. The long time hot plasma confinement is provided by a magnetic trap configuration of the magnetic field.



I. M. Podgorny, A. I. Podgorny, S.Minami, and M. Morimoto. MHD Model for a Heliospheric Current Sheet. Astronomy Reports, 48, No. 5, 2004, pp. 433–438.


A numerical solution of the full set of MHD equations shows the generation of a heliospheric current sheet during the thermal expansion of the corona. Calculations were performed for a compressible plasma taking into account dissipative terms and anisotropy of the thermal conductivity of the magnetized plasma.
The heliospheric current sheet contains a normal component of the magnetic field, which plays a fundamental role during the formation of the sheet and in the stationary state. The sheet is stable against MHD perturbations, which are apparently carried away by the plasma flow. The drop of solar wind velocity is observed in the heliospheric current sheet.

2008

Подгорный А. И. и Подгорный И. М. Образование нескольких токовых слоев над активной областью АО 0365 перед серией вспышек. Астрономический Журнал. 85, 739-749 (2008). (Astronomy Report., 52, No. 8, 666–675 (2008).

3D MHD modeling has demonstrated the formation of several current sheets above the active region before a series of flares observed on May 26–27, 2003. Each current sheet could be responsible for an elementary flare.

The proof of the current sheet formation before a flare.

The mechanism of energy accumulation in the corona for solar flares was studied by several authors. The various possibilities of occurrence of solar flares were considered: the acceleration of a magnetic rope accompanied by pulling the field lines of a magnetic arch (Lin et al., 2004), the instability of a magnetic rope formed by rotation of sunspots (Torok, Kliem, 2010), and injection of magnetic helicity (Kusano et al., 2004; Chae, Moon & Park, 2004), at al. When setting the initial conditions in numerical MHD simulation of these processes, (Kusano et al., 2003) assumptions are made about the mechanism of are process development. In the present here works no assumption is used about solar flare model. The flare model based on a current sheet creation is shown from results of numerical 3D MHD simulation. The appearance of a current sheet before the flare is demonstrated in the numerical experiments, where initial and boundary conditions are set using preflare measurements in the active region.

The current sheet creation above an active region before the flare has been demonstrated in numerical solution of the full system of 3D MHD equations with all dissipative terms. The magnetic _field measured by SOHO MDI (http://soi.stanford.edu/magnetic/index5.html) on the photosphere is used for setting initial and boundary conditions. Magnetic field distribution is taken from magnetic maps. In this numerical experiment no assumptions are used about the solar model and about a possibility mechanism of energy accumulation for a flare. It is shown that the current sheet is created during several days before the flare due do disturbances arriving from the photosphere and focusing these disturbances in the vicinity of a singular magnetic line. In the simplest case, the new magnetic flux slowly emerges before a flare. The magnetic field of emerged field is directed opposite to the magnetic field already existing in the active region. The weak current sheet appears in 2 - 3 days before the flare. During this time the current sheet becomes stronger and stronger. It accumulates the magnetic energy for the flare. Such a current system should be capable to accumulate free magnetic energy and release it fast at transition in an unstable state producing a flare. The results of numerical experiment show that typical magnetic energy stored before the big flare is 1032 - 1033erg (Bilenko, Podgorny, and Podgorny, 2002). This energy can be released due to CS transition into an unstable condition (Podgorny, 1989).


2005 - 2010

Prompt and delayed components of solar cosmic rays.

Most of big solar flares are accompanied by relativistic proton emission. The prompt component of relativistic protons moves along the interplanetary magnetic field lines and arrives at the Earth’s orbit when the flare favorably located in the western solar hemisphere. The neutron monitor measurements reveal the exponential law energy spectrum. Calculations of relativistic proton acceleration in the flare current sheet with magnetic and electric fields found from 3D MHD simulations also demonstrate the exponential spectrum. A comparison of the measured and calculated spectra permits for the first time to estimate the rate of magnetic reconnection in the Bastille flare (July 14, 2000) as ~107 cm/s. The delay component of relativistic protons exhibits a power energy spectrum. Scattering on magnetic fluctuations can be a reason for the formation of the power law spectra.


2011

The connection between the magnetic flux of the active region and the powerful flares.

The behavior of active regions during the passage through the disk of the Sun that produce series of class X flare is investigated. Flares of X class appear, when the magnetic flux becomes 1022 Max. The flow of energy from the photosphere into the corona at flare was not observed. The behavior of the photospheric field in active regions AR10486, AR10365, AR 10720 is consistent with the explosive release of energy stored in the magnetic field of the current layer above the active region. Maps SOHO MDI represent the distribution of the magnetic field component directed along the line of sight. With the passage of the active region on the disk the angle between the line of sight and the normal to the surface changes. So, recorded the field distribution depends on the position of the active region on the solar disk. The initial research task was to calculate the distributions of normal component of the magnetic field, using data from SOHO MDI.


Podgorny A. I., Podgorny I. M. Magnetic Flux in an Active Solar Region and Its Correlation with Flares Astronomy Reports, 2011, Vol. 55, No. 7, pp. 629–636.

2012

Magnetic flux and the magnetic field distribution in the active region are preserved during big flares with an accuracy of 1%. This result points to the release of energy flare in the corona. The reservoir of free energy for the flare may be a current sheet.


Podgorny I.M., Podgorny A.I. J. Atm. Sol. Ter. Phys. (2012). In Press


Подгорный Игорь Максимович (e-mail)