Злотник Елена Яковлевна
ведущий научный сотрудник  сектора физики плазменных процессов в атмосферах Солнца и планет,
Отдел астрофизики и физики космической плазмы.
д.ф.-м.н.,  старший научный сотрудник
(в настоящее время на пенсии) 

zlot@appl.sci-nnov.ru,  zlotnik@inbox.ru

Родилась в 1939 г. в г.Горьком, вдова

Образование:
В 1962 г. окончила радиофизический факультет Горьковского государственного университета по специальности радиофизика, в 1965 г. окончила аспирантуру под руководством В.В.Железнякова. В 1975 г. защитила кандидатскую диссертацию на тему "Некоторые вопросы генерации и распространения электромагнитных волн в плазме солнечной короны". В 1999 г. защитила докторскую диссертацию на тему "Диагностика плазмы солнечной короны по наблюдаемому радиоизлучению".

Область профессиональных интересов:
Физика космической плазмы, радиоизлучение Солнца и планет.

Профессиональная карьера:
Работала в Научно-исследовательском радиофизическом институте (НИРФИ) в должности младшего научного сотрудника, старшего инженера, с 1997 г. в Институте прикладной физики РАН в должности старшего научного сотрудника и с 2000 г. в должности ведущего научного сотрудника.
Была с научными визитами в Гражданской и промышленной организации Австралии (CSIRO), Мерилендском университете в США, Астрономическом институте Потсдама в Германии и ряде других научных организаций.

Членство в профессиональных организациях:
Член Международного Астрономического Союза (IAU), член Европейского астрономического общества, Член Российского астрономического общества.

Награды, премии, гранты:
Грант  Южно-Европейской Обсерватории, 1993, 1994.
Грант фонда Сороса, 1993, 1994, 1995.
Грант астрономического института Потсдам, 1993, 1995, 1997, 1999.
Грант  INTAS, 1995.
Грант РФФИ, 1995, 1998,  2001, 2004, 2007, 2010,  2013.

Педагогическая деятельность:
Чтение курса лекций по астрофизике на вечернем отделении физического факультета ННГУ в 1983-1988 г.г., курс лекций "Астрофизика для радиофизиков" на 4-м курсе радиофизического факультета ННГУ (для бакалавров) в 1993-2001 г.г.

Публикации:
Свыше 120 научных публикаций.

Наиболее значительные работы и результаты:

1. Е.Я.Злотник, К теории медленно меняющейся компоненты солнечного радиоизлучения, Астрон. ж. 1968, Т.45, № 2, С.310-320, № 3, С. 585-596.
Предложена модель активной области на Солнце, в рамках которой рассчитаны характеристики медленно меняющегося радиоизлучения, вызванного совместным действием тормозного и магнитотормозного механизмов. Показано, что принятая схема генерации объясняет основные особенности s-компоненты: распределение радиояркости по источнику, характерный частотный спектр с максимумом на волнах 6-12 см, зависимость поляризации от длины волны, изменение размера и высоты источника с частотой характер направленности излучения, связь с оптическими характеристиками центров активности. Выяснена относительная роль обоих механизмов в суммарном излучении: тормозное излучение является определяющим в коротковолновой части сантиметрового диапазона ( см) и на дециметровых волнах ( см), а магнитотормозной механизм дает основной вклад в интервале , где частотный спектр имеет максимум. Подробно обсуждена выбранная модель локального источника. Указаны способы, позволяющие по известным характеристикам s-компоненты судить о физических условиях (температуре концентрации плазмы, магнитном поле) в активных областях на Солнце.  

2. V.V.Zheleznyakov, E.Ya.Zlotnik, On the third harmonic in solar radio bursts, 1974, Solar Phys., V.36, p.443-449.
Generation of third harmonic plasma emission by coalescence of second harmonic radiation with a plasma wave is more favourable than by direct coalescence of three plasma waves. The predicted ratio of the intensities at the third (III) and second (II) harmonics is , where is the plasma frequency,  is the energy density in plasma waves, is the linear dimensions of the source and  is the ambient electron plasma density. The intensity at the second harmonic is  , where    is the typical dimension of coronal inhomogeneities.  It is suggested that the third harmonic in a U-burst observed by haddock and Takakura and in type V emission reported by Benz (1973) were due to this process.  For the latter event the theory predicts  compared with the observed ratio of 10-1.

3. V.V.Zheleznyakov, E.Ya.Zlotnik, Cyclotron wave instability in the corona and origin of solar radio emission, 1975, Solar Physics. I. Bernstein modes and plasma waves in a hybrid band, V.43, P. 431-451, II. Origin of tadpoles, V.44, P. 447-459, III. Origin of zebra-pattern, V.44, P. 461-470.  
The longitudinal waves (Bernstein modes and plasma waves near the hybrid frequency) in a mixture of equilibrium coronal plasma and a small group of energetic electrons are investigated. The energetic electrons have a nonequilibrium momentum distribution inherent in trapped particles. The frequency dependence of the cyclotron instability increments is studied. Attention is paid to a significant role of the relativistic effects for the cyclotron instability of longitudinal waves. For sufficiently large velocity of nonequilibrium electrons the increments are shown to increase when the hybrid frequency coincides with one of the gyrofrequency harmonics (double plasma resonance). The results obtained are used in Parts II and III to explain 'tadpoles' and 'zebra'-pattern in solar radio bursts.
An interpretation is suggested of the fine structure of tadpole solar radio emission based  upon the theory of Bernstein mode cyclotron instability. It is shown that the frequency spectrum of an individual tadpole is similar to the frequency behavior of the Bernstein mode increment if the velocity of electrons trapped by the magnetic field amounts nearly to 109cm/s.  The absorption “body” and emission “tail” are associated  with the instability due to the kinematic Doppler effect and the “eye”  with the instability due to the velocity dependence of the electron mass. The observed radio emission is the result of nonlinear conversion (coalescence) of Bernstein modes at different frequencies  into electromagnetic waves. The appearance of separate tadpoles (interrupted character of emission in time)  is attributed to the pulse injection of the nonequilibrium electrons into the trap. Estimations are presented for the expected dimensions of emission region and the hot electron density necessary for  Bernstein mode excitation.    
The results of investigation of the cyclotron wave instability in the corona for Bernstein modes and plasma waves in a hybrid band have been used to interpret zebra-pattern phenomena. Two models of the generation region of parallel drifting bands are considered: the model of the point source localized at the apex of the magnetic trap and the model of a distributed source extended along the magnetic flux tube. In the first model it is assumed that a harmonic character of zebra pattern appears either in coalescence of excited Bernstein modes at different harmonics of the gyrofrequency or in coalescence of these modes with plasma waves excited in the hybrid band. In the latter case if the magnetic field changes in time a pulsating generation regime occurs. In the second model, the emission bands appear in the regions of double plasma resonance as a result of coalescence of longitudinal waves excited in the hybrid band. Estimations of the magnetic field and the nonequilibrium component density necessary for the zebra-pattern to generate are presented.

4. E.Ya.Zlotnik, The polarization of second harmonic emission in type III bursts, 1981, 
Astron.Astrophys., 1981, V.101, P.250-258.
The conversion of plasma waves into magneto-ionic modes in the solar corona is discussed as a possible origin of observed polarization of the second harmonic radio emission in Type III bursts. It is shown that earlier paper (Melrose and Sy, 1972; Melrose, Dulk and Smerd, 1978) concerning the subject involve an inaccuracy which results in omitting some important terms in the expression for the probability of longitudinal wave coalescence. In the present paper the problem is carefully analyzed. Along with the o-mode excess evident from the earlier theory, revised calculations explain the cosine law for centre-to-limb distribution of the second harmonic polarization. Observational data are in good agreement with the theory provided that the plasma waves excited by coronal electron streams and responsible for Type III bursts have nearly one-dimensional angular distribution. Corrected formula implies the magnetic fields in Type III sources to be of order B 4 Gauss. This field is stronger than that estimated by the fundamental polarization.

5. V.V.Zaitsev, V.E.Shaposhnikov, E.Ya. Zlotnik, The origin of S-bursts in Jupiter’s decametric radio spectra, Astron. Astrophys. 1986, V.169, P.345-354.
A model for Io phase dependent S-bursts in Jupiter's decametric radio emission is proposed. The source region is a multi-component system composed of an  equilibrium plasma and an admixture of loss-cone ions and electrons. The system is localized in the Jovian ionosphere at the foot of the Io flux tube, in the region of a strong () quasi-homogeneous magnetic field. Different types of conversion of plasma waves into electromagnetic waves lead to quasi-periodic trains of S-bursts and isolated simple S-bursts. The negative frequency drift is due to the group delay of extraordinary waves during their propagation in the region with low refractive index (). The strong beaming explains the Io phase dependent S-bursts. The central meridian longitude phase control is due to the fact that Io traverses periodically the region of increased plasma density (plasma torus) and that the number of particles reaching the source increases.

6. В.М.Богод, В.И.Гараимов, В.В.Железняков, Е.Я.Злотник, Обнаружение циклотронной линии в спектре микроволнового излучения активной области на Солнца и ее интерпретацияб 2000, Астрон. ж., Т.77, № 4, С. 313-320.
Приведены данные наблюдений активной области AR 7962 10-12 мая 1996~г. в диапазоне 2--32 см на радиотелескопе РАТАН-600. На фоне гладкого частотного спектра локального источника, связанного с пятнами, измерения с высоким разрешением по частоте выделили узкополосную деталь на волне около 8.5 см. Это узкополосное излучение отождествлено с ярким точечным источником высокочастотного излучения на волне 1.7 см, зарегистрированным на картах радиотелескопа в Нобеяма.  Характеристики наблюдаемой линии  (время жизни 3 дня, яркостная температура порядка нескольких миллионов Кельвин, относительная ширина около 10\%) допускают ее объяснение как теплового циклотронного излучения из компактного источника, содержащего плотную горячую плазму, на третьей гармонике электронной гирочастоты, а соответствующее высокочастотное излучение может быть обязано своим происхождением тепловому тормозному механизму. Анализ данных РАТАН-600 и Нобеяма позволяет провести диагностику магнитного поля, кинетической температуры и электронной концентрации в источнике
излучения в короне.

7. H.Aurass, K.-L.Klein, V.V. Zaitsev, E.Ya.Zlotnik, Solar type IV burst spectral fine structures, 2003,  Astron.Astrophys., V.410.  I. Observations, P. 1001, II. Source model,  P.1011.
The fine structures (FS) of solar type IV radio bursts are of principal interest for flare plasma diagnostics in the low corona. In this paper we give an observational (Part I) and theoretical (Paper II) treatment of broad band radio pulsations (BBP) and zebra patterns (ZP) in a well observed flaring sigmoidal loop system of AR 7792 on 25 October 1994. We present comprehensive meter-decimeter radio spectral (Astrophysical Institute Potsdam, AIP) and meter wave heliographic (Nançay Radio Heliograph of Paris-Meudon Observatory, NRH) observations. Spectral and spatial properties of FS elements (one pulsation pulse, one single zebra stripe) as well as a statistical analysis for the whole fine structure event are presented. The source sites are compared with soft X-ray images of the flare, and with force-free extrapolated coronal magnetic fields. Both FS sources occur in a common diverging loop structure with a turning height of about 70 Mm. The BBP source is shown to appear (if seen along the loop axis) nearer to the injection site of the electrons than the ZP source. BBP do show high frequency drift (~-250 MHz s-1). At a given frequency, the projected source speed is 1.1x 105 km s-1. For ZP, we find a good correlation between the inclination of a single zebra stripe to the heliographic observing frequency level in the dynamic spectrogram, and the speed of the simultaneously observed projected source motion at this frequency. The direction of the source motion at a given frequency is on average found to be perpendicular between BBP and ZP sources. During a time interval of 90 s the BBP source consists in its lower part (higher observing frequencies) of a widely spaced double source. Despite a source distance of 360 Mm both subsources are highly correlated and thus probably simultaneously driven. We come to the conclusion that both fine structures are emitted during repeated electron beam injection into an asymmetric magnetic trap configuration between a footpoint in the leading spot of AR 7792 and a trailing more dispersed footpoint. In Paper II we will show that the specifications derived from the data allow for selecting one out of several competing fine structure models which explains the simultaneous formation of BBP and ZP in the same loop structure.
We discuss a source model for the origin of solar type IV burst fine structures (FS) using the data of an event in AR 7792 on 25 October 1994. After giving a comprehensive observational treatment of FS (Paper I), here we repeat the main observed facts to construct a simplified radio source model. It consists of two interacting loops (named LS1 and EL) with one spatial order of magnitude scale difference (turning heights 70 and 7 Mm). We consider the implications of this model for physical mechanisms of broad band pulsations (BBP) and zebra patterns (ZP). Our analysis leads to the conclusion that meter wave BBP and ZP originate from a common magnetic source structure - a large asymmetric coronal loop. It is shown that the BBP result from periodically repeated injections of fast electrons into the asymmetric magnetic trap. The excitation of plasma waves is due to the stream instability when these electrons are propagating along the loop. We demonstrate that a two percent quasi-periodic modulation of a magnetic field component in EL is sufficient for it to act as a periodic electron accelerator. The ZP is due to a plasma wave instability at the levels of double plasma resonance (DPR) in an inhomogeneous source distributed along the loop axis of LS1. The DPR frequencies appear at those height levels where the upper hybrid frequency is equal to a harmonic of the gyrofrequency. Two Appendices review theoretical details needed to understand the given ZP interpretation. The gyrofrequency as a function of height was derived from a force-free extrapolated field line that passes the coronal radio source. After knowing the loop turning height and the magnetic field strength we identified for a fixed observing time the harmonic number of each zebra stripe. The comparison of the calculated DPR levels with the observed zebra stripe peak frequencies yields a density law for the ZP source volume. It turns out that this is a barometric law with a temperature near 106 K. We demonstrate that the drift of the whole ZP to higher frequencies can be explained as a signature of magnetic field decrease and/or plasma cooling in the ZP source. The time delay between BBP and ZP was found to be due to the higher fast particle threshold of the DPR versus the beam instability. The present analysis confirms the double plasma resonance model for the ZP fine structure, and underlines the significance of force-free extrapolated photospheric fields for coronal magnetic field modelling.

8. E.Ya.Zlotnik, Origin of Zebra Pattern in Type IV Solar Radio Emission, 2009, Cent. Eur. Astrophys.Bull., V.33, P.281.
Strong and weak aspects of different theories of fine structure on solar radio emission dynamic spectra observed as several or numerous quasi-equidistant bands of enhanced and reduced radiation (zebra pattern) are discussed. Most of the works which propose zebra pattern interpretation are based on the plasma mechanism of radio emission generation, which consists of excitation of plasma (electrostatic) waves and their subsequent transformation into electromagnetic emission. Plasma waves arise due to kinetic or hydrodynamic instability at the upper hybrid frequencies at the levels of double plasma resonance in a distributed source. Some works are devoted to considering whistlers as the main reason for stripes in emission and absorption occurring in the dynamic spectra. An alternative theory of zebra pattern origin suggests that of a compact source with trapped plasma waves is present in the corona. Another interpretation is based on special effects that may occur when radio waves propagate through some periodic structure in the corona. All suggested mechanisms are analyzed with relation to their capability to give the best fit for the observed fine structure features in the framework of the source model with reasonable physical parameters. It is shown that the theory based on the effect of double plasma resonance in a non-homogeneous coronal loop is the best-developed theory for the origin of zebra pattern at the meter-decimeter wavelengths at the present time.

9. E.Ya.Zlotnik , Instability of  Electrons Trapped by the Coronal Magnetic Field and Its Evidence in the Fine Structure (Zebra Pattern) of Solar Radio Spectra, 2013, Solar Physics, V.284, P. 579–588.
Solar radio emission is a significant source of information regarding coronal plasma parameters and the processes occurring in the solar atmosphere. High resolution frequency, space, and time observations together with the developed theory make it possible to retrieve physical conditions in the radiation source and recognize the radiation mechanisms responsible for various kinds of solar radio emission. In particular, the high brightness temperature of many bursts testifies to coherent radiation mechanisms, that is, to plasma instabilities in the corona. As an example, the fine structure of solar radio spectra looking like a set of quasi-harmonic stripes of enhanced and lowered radiation, which is observed against the type IV continuum at the post-flare phase of activity, is considered. It is shown that such emission arises from a trap-like source filled with a weakly anisotropic equilibrium plasma and a small addition of electrons which have a shortage of small velocities perpendicular to the magnetic field. For many recorded events with the mentioned fine spectral structure the instability processes responsible for the observed features are recognized. Namely, the background type IV continuum is due to the loss-cone instability of hot non-equilibrium electrons, and the enhanced striped radiation results from the double-plasma-resonance effect in the regions where the plasma frequency  coincides with the harmonics of electron gyrofrequency  . Estimations of the electron number density and magnetic field in the coronal magnetic traps, as well as the electron number density and velocities of hot electrons necessary to excite the radiation with the observed fine structure, are given. It is also shown that in some cases several ensembles of non-equilibrium electrons can coexist in magnetic traps during solar flares and that its radio signature sensitively depends on the parameters of the distribution functions of the various ensembles.              

10.  E.Ya.Zlotnik, V.V.Zaitsev, A.T.Altyntsev,  On Polarization of the Zebra Pattern in Solar Radio Emission, 2013, Solar Physics, DOI 10.1007/s11207-013-0327-3.
The problem of strong polarization of the zebra-type fine structure in solar radio
emission is discussed. In the framework of the plasma mechanism of radiation at the levels of the double plasma resonance, the polarization of the observed radio emission may be due to a difference in rates of plasma wave conversion into ordinary and extraordinary waves or different conditions of escaping of these waves from the source. In a weakly anisotropic plasma which is a source of the zebra-pattern with rather large harmonic numbers, the degree of polarization of the radio emission at twice the plasma frequency originating from the coalescence of two plasma waves is proportional to the ratio of the electron gyrofrequency to the plasma frequency, which is a small number and is negligible. Noticeable polarization can therefore arise only if the observed radio emission is a result of plasma wave scattering by ions (including induced scattering) or their coalescence with low-frequency waves. In this case, the ordinary mode freely leaves the source, but the extraordinary mode gets into the decay zone and does not exit from the source. As a result, the outgoing radio emission can be strongly polarized as the ordinary mode. Possible reasons for the polarization of the zebra pattern in the microwave region are discussed.