S. S. Ananyev

Spectroscopic measurements of the parameters of the helium plasma jets generated in the plasma focus discharge at the PF-3 facility

The spectroscopic technique used to measure the parameters of the plasma jets generated in the plasma focus discharge and those of the plasma of the immobile gas through which these jets propagate is described. The time evolution of the intensities and shapes of spectral lines in experiments carried out with helium at the PF-3 facility was studied by means of electron-optical streak cameras. The plasma electron temperature, T ≈ 4–5 eV, was determined from the intensity ratio of two spectral lines, one of which (λ1 = 5876 Å) belongs to neutral helium, while the other (λ2 = 4686 Å), to hydrogen-like helium ions. The plasma density at different time instants was determined from the Stark broadening of these lines in the electric fields of different nature. The plasma density is found to vary from 4 × 1014 to 2 × 1017 cm−3.

Study of Plasma Flows Generated in Plasma Focus Discharge in Different Regimes of Working Gas Filling

Results are presented from experimental studies of the plasma flows generated in the KPF-4 Phoenix Mather-type plasma focus device (Sukhum Physical Technical Institute). In order to study how the formation and dynamics of the plasma flow depend on the initial distribution of the working gas, a system of pulsed gas puffing into the discharge volume was developed. The system allows one to create profiled gas distributions, including those with a reduced gas density in the region of plasma flow propagation. Results of measurements of the magnetic field, flow profile, and flow deceleration dynamics at different initial distributions of the gas pressure are presented.

INVESTIGATION OF THE PULSED PLASMA FLOW, GENERATED IN NON-CYLINDRICAL Z-PINCH SYSTEMS, BY ELECTRON-OPTICAL METHODS

В последнее время наблюдается значительный рост интереса к генерируемым в Z-пинчевых системах плазменным потокам. Это связано как с пониманием роли процессов, приводящих к генерации потоков, в общей физике формирования и динамики пинча, так и с все возрастающим практическим использованием этих потоков. В работе описана система щелевого электроннооптического фотографирования в видимом диапазоне, созданная для исследования динамики импульсных плазменных потоков, вызванных сжатием Z-пинча. Эксперименты проведены на установке ПФ-3, крупнейшей в мире среди представителей одной из разновидностей Z-пинчевых систем — плазменный фокус. Приведены первые результаты измерений скорости плазменных потоков при использовании различных рабочих газов (водород, неон, аргон). Показана структурированность плазменного потока. Обнаружено отсутствие существенной зависимости скорости потока от сорта рабочего газа.

INVESTIGATION OF FORMING PLASMA FLOW GENERATED IN PLASMA FOCUS DISCHARGE

На плазменном фокусе ПФ-3 методами скоростной фоторегистрации исследована стадия формирования пинча, являющегося источником аксиального плазменного потока. Основной упор был сделан на регистрацию начального момента генерации потока. Комбинация нескольких щелевых развёрток, размещаемых в различных направлениях и на различном удалении от плоскости анода, позволила воссоздать пространственную картину формирования аксиальных потоков вещества. Обнаружены потоки вещества, распространяющиеся быстрее (1,310 см/с), чем плазма, вытесняемая по оси магнитным поршнем (0,510 см/с). Вероятнее всего, именно эти потоки вещества наблюдаются на значительном удалении от анода в виде компактных джетов.

Study of the anode plasma dynamics under the action of a high-power electron beam on epoxy resin

Results are presented from experimental studies of plasma dynamics in a diode gap under the action of a high-current relativistic electron beam on epoxy resin at energy densities in the range of 170–860 J/cm2. The plasma expansion was studied by means of an optical streak camera. Three-dimensional numerical simulations in the one-temperature hydrodynamic approximation were also performed. The experimental data are compared with the results of numerical simulations.

PARAMETERS OF THE PLASMA STREAMS FROM THE PLASMA FOCUS IN EXPERIMENTS ON THE PF-3 FACILITY

Представлены оптические спектральные методики и результаты измерения температуры и концентрации плазмы в аксиальных струях, полученные в рамках экспериментов по лабораторному моделированию динамики астрофизических джетов, проводящихся на установке ПФ-3. Концентрация плазмы определялась по форме штарковских контуров спектральных линий, ионизационная температура — по отношению интенсивности спектральных линий атомов и ионов или по степени ионизации. Приведены значения концентрации и температуры плазмы струй из разных газов — водорода, гелия и неона на расстояниях 35 и 65 см от плазменного фокуса.

Behavior specificities of the plasma in the REB - polymeric anode interactions.

To study Relativistic Electron Beam (REB) interaction with a set of polymeric targets we have made experiments for the investigation of the plasma dynamics in high-voltage diode of high-current generator. It is necessary for applied goals, such as correction of mathematical models of high power density deposition in the matter, for testing materials reaction under the powerful impulse of ionizing radiation, etc. An electron-optical streak camera (EOC) was used to measure the velocity of the visible light border of the plasma glowing. It was estimated to be from 10 to 35 km/s at the energy-release density in range of 200 - 800 J/cm2. In a few of experiments, besides regular motion of contrast border in the direction from electrodes to the middle of the diode, the motion from the middle to the periphery of the high-voltage diode with velocity up to 500 km/s was observed. It was by an order of magnitude greater than regular one.

A spectroscopic complex for time-resolved registration of plasma-jet parameters at the PF-3 facility

A spectroscopic complex for measuring the parameters of plasma jets that are generated in a facility of the plasma-focus type and the parameters of a stationary gas in which these jets propagate is described. The complex consists of an STE-1 crossed-dispersion spectrograph and a K008 streak camera, which is placed together with a notebook computer and a no-break power unit inside a shielding box for protection against electromagnetic noise. The K008 camera is equipped with an additional image intensifier on the basis of an EP-10 image-converter tube. The spectrum image is recorded with a standard SU-05M video camera and processed with the Klen-5m dedicated program, which automatically corrects the distortion and scan nonuniformities and subtracts regular noise. The complex makes it possible to obtain the time dependences of the intensities and shapes of several spectral lines in a range of scans from a few nanoseconds to milliseconds and to promptly tune the system to the required spectral ranges. Within one discharge of the facility, a digital image of the time-integral spectrum is simultaneously recorded in the entire visible region.