Spicules are intermittently rising above the surface of the Sun eruptions,EUV jets are now also reported immediately above surface layers. The orientation of spicules is a valuable parameter in the absence of direct magnetic field measurements with a sufficient spatial resolution in the chromospheric region because it is presumably determined by the confined flow of plasma, which should occur along the magnetic field lines, especially where the solar magnetic field pressure dominates the gas pressure. Of course, all these measurements suffer from the overlapping effect of spicules seen along each line of sight, the effect of which will be more critical when we look near the solar limb. In the case of macrospicules as well imaged by AIA of the SDO mission using the 304 filter recording the emissions of the HeII, resonance line, an additional effect arises due to the optical thickness of the line, especially on disk and also above the limb in the inner chromospheric shell. The primary purpose of this paper is to determine automatically and objectively the apparent tilt angle of spicules, using the best available highly processed observations, from the Solar Optical Telescope (SOT) limb imaging experiment by using an H CaII line, onboard Hinode mission. Furthermore, the Hough transform is applied to the resulting images for making a statistical analysis of spicule orientations in different regions around the solar limb, from the pole to the equator. A technique for the automatic detection off-limb spicules was implemented, and statistical measurements were conducted to determine the tilt angle for spicules at different heliocentric angles. We apply and develop a method with the following steps: (1) To increase the visibility of spicules, a radial logarithmic scale is applied,(2) To enhance linear features, while the Madmax operator is used. We investigated in more detail the apparent inclination of spicules and found the statistically average values for different locations around the solar limb for tilt angle. The results show a large difference of spicule apparent tilt angles in (i) the solar pole regions, (ii) the equatorial regions, (iii) the active regions, and (iv) the coronal hole regions. Analytically, during the minimum solar magnetically activity, from the equator to the poles, the inclination angles of the spicules are getting smaller and their lengths increase. As a result, the chromosphere thickness in this case is thicker than that of the solar maximum activities. When the spicules in the polar coronal holes are significantly inclined, the chromosphere and even transition regions thickness is thinner. Numerically, spicules are visible in a radial direction in the polar regions with a tilt angle <200. The tilt angle is even reduced to 10 degrees inside the coronal hole with open magnetic field lines and at the lower latitude, the tilt angle reaches values over 50 degrees. Usually, around an active region, they show a wide range of apparent angle variations from-60 to +60 degrees, which is in close resemblance to the rosettes that are made of dark mottles and fibrils in projection on the solar disk. However, large-scale activities with short life-time do not play a significant role in the thickness of the chromosphere, and they are removed for long term measurements by averaging. Therefore, this study considers the most statistical population of spicules in the minimum (and maximum) solar activity in the polar regions, and in lower latitude, to be considered as their inclination angles. While at the maximum laps of solar cycle, the opposite result will be expected, and fully confirmed, and give us a topological reason for the chromospheric prolateness at minimum activities.

In this article, we analyzed the abnormal thickness of the chromosphere above the coronal holes (CH) at the poles of the Sun for 13 years (2010-2022), on the 15th of every month, by using AIA/SDO telescope data. We used the light emitted from helium-2 (He II) at a wavelength of 304 {AA} at about 50,000 K to investigate the solar holes in its north and south poles. This light is emitted from the chromosphere and the transition region. According to the values of the graphs obtained by the MATLAB program and the comparison between solar cycles during the 2010-2022 years, it was seen that the Full width of the intensity curves at half maximum (FWHM) in the poles, and as a result the magnetic activity of the sun and especially the activity of coronal cavities as the main source of the solar dipole magnetic field before cycle 25 is significantly greater than this thickness before cycle 24. According to the relationship between the number of sunspots and the solar activity in the coronal holes at the solar poles with a time delay of 2 to 5 years, we expect the maximum increasing in the number of sunspots around the year 2025. As a result,in terms of the number of sunspots, the height of the solar cycle 25 probably is higher than the cycle 24, which was a low sunspot number cycle. We also concluded that the thickness of the Chromosphere has an inverse relationship with solar dynamo magnetic activity cycle.

Sound waves have the potential to transfer the energy needed to heat the sun's atmosphere from the lower layers to higher areas. The source of these waves can be the surface oscillations of the sun, the most famous of which are the 5-minute oscillations. In this research, we investigate the propagation of sound waves in the first 2000 km of the sun's atmosphere, which is known as the chromosphere. In the chromosphere, variations in plasma density, hydrodynamic pressure, and temperature with height cause wave propagation to be complicated. Here, we build a chromospheric model using observational data and investigate sound propagation in both pulse and wave train modes. We solve the equation of motion numerically in the linear regime using the finite difference method. The results show that due to the reflection of the wave in different layers of the atmosphere, the sound pulse does not maintain its original shape, instead, its energy is spread in a wide space of the atmosphere. Also, for sinusoidal wave trains at different frequencies, we obtain the amount of the energy of the wave penetrating to the upper layers. Results show that as the frequency of the wave increases, the capability of the wave to transfer the acoustic energy from the photosphere to the upper chromosphere increases.

Simultaneous observations of the Interface Region Imaging Spectrograph (IRIS) data, with a spatial resolution of less than one second consisting of ultraviolet (UV) spectra and images (SJI), make it possible to investigate solar chromosphere and transition region and provide valuable information about the dynamics of solar jets. IRIS combines numerical modeling, high resolution imaging, and UV spectroscopy. The interface region is the main place for the transfer of energy from the solar surface to the very hot corona. Of course, knowing the secret of energy transfer in the solar atmosphere is not the only goal of this mission, but also it examines the solar winds that is emitted from this area, which carry a rain of charged particles into space and also affect the Earth's climate. Information about the dynamic behavior of the physical phenomena of the solar atmosphere is obtained by studying the characteristics of spectral lines. For this purpose, it is necessary to obtain the information to identify and study spectral lines and how they are formed. The solar atmosphere is a plasma environment associated with a variety of transient events. Astrophysicists, especially in the field of solar dynamic physics, describe these events by magneto-hydrodynamics aspect. One of these phenomena is the bright spots of the solar atmosphere called jets. We identify and study the dynamics of a series of jets recorded on August 17, 2014, at Mg II k, C II and Si IV spectral lines corresponding to the 2796 Å, 1336 Å, and 1394 Å wavelengths, respectively. Jets are small-scale dynamic events that can be detected by non-Gaussian profiles of lines in the solar chromosphere and transition region. The production mechanism of these plasma jets is still being investigated. We use the temporal evolution analysis method to track the path of these structures and determine their apparent velocity. To calculate the Doppler velocity we perform Gaussian fitting at the same time on the spectral intensity profiles. The apparent velocity results show that these jets have quasi-periodic motions with speeds of approximately 10 to 110 kms-1. Spectral investigation of these jets also shows the periodic behavior that is associated with increasing in blue and red wings at the three wavelengths as-65 to 40, 60 to 50, and 80 to 60 kms-1, respectively. Simultaneous enhancements in the blue and red wings of the spectrum can be caused by two-directional upward currents caused by magnetic reconnection and amplified by waves with p-modes (compression modes). According to these results, it is suggested that the fluctuations in these events with increasing on one side of the spectrum and both sides of the wing are signs of spiral and rotational motions, respectively. The results of this research show that by using the data of the IRIS Telescope, it is possible to identify and extract the physical components of jets at different wavelengths and identify their dynamic behavior. These specifications will help us better understand the stratification of the solar atmosphere and how heat and matter are transferred to the sun's surface and the effects of such transitions on the Earth's atmosphere. The application of this study will be the goal of space research and is very important in identifying space and Earth’s climate.

The similarities between Ca and x-ray jets suggest that their formation mechanism should be the same. Surges are almost cool plasma jets and are usually observed in Hα at ground-based observation, space observations also detect Surges. The structure and movement of the observed surges and jets necessitate a reconnection framework in which magnetic tension and the release of twisted energy contribute significantly. Convincing indications of reconnection are offered by whip-like movements, and the rotational behavior of the surges arises as an outcome of the relaxation of reestablished magnetic twist. The IRIS spectra spicules to determine one of the factors affecting the production and feeding of solar winds. Jets and spicules have been considered by examining several raster frames from the regions of the Sun. The characteristics of spicules, such as the rotational velocity of each spicule concerning the central axis of the spectrum , were computed using the output of the Doppler map. Then, using the Mg II spectrum simultaneously, Doppler maps for specific index samples were created at various speeds. Based on the results, a speed of 30 km/s was demonstrated.Our investigation into spicules unveiled a distinctive type that deviates from prior observations regarding speed, angle, and direction of movement. These spicules appear to result from vortical movements, which could also contribute to the propagation of Alfvén rotational waves and the transfer of energy to the Sun's upper atmosphere. In this study, it is essential to recognize that rotating spicules represent minute structures observable in exceedingly high-resolution imaging.

In this study we review solar chromospheric jets and characteristics of them. The chromosphere and transition region are the interface between the solar photosphere and the corona, which plays a key role in the formation and acceleration of the solar wind. In recent years, scientists have made great efforts to understand the mechanism of energy transfer in the solar chromosphere and corona. The researchers suggest that the key to solving this problem may lie in understanding the nature of the small-scale transient events that are distributed across the surface of the Sun. Of these, solar spicules are the most prominent small-scale dynamical phenomena in the chromospheric regions that drive relatively cold material from the lower chromosphere to the corona. Spicules can heat the corona both by ejecting hot plasma and by energy transfer by magnetohydrodynamic (MHD) waves. These dynamical structures are formed when photospheric oscillations and convective flow along the magnetic field lines penetrate into the chromosphere.

A distinct difference is seen between different parts of the solar  chromosphere, including the bright points (BPs) at the boundary and within the network, and the darker regions formed the interior of the granules. In the photosphere, apart from sunspots and holes, there are direct and concentrated magnetic fields in the form of small flux tubes with fields of 1 to 2 kG. Chromospheric networks are highly dynamic regions with fine structures embedded in the magnetic flux. These structures are located inside the cell network and there are also many small and dark cells around it. BPs can be thought of as trails of spicules through which mass and energy from the lower layers of the Sun are transported to the corona as the solar wind. Although in the last two decades, despite high-resolution observations and theoretical advances, effective steps have been taken to determine dynamics of BPs and various thermodynamic parameters such as temperature and density, but the mechanisms responsible for their formation are still unknown. These ambiguities are due to the difference in their appearance as a result of observation at different spectral lines and wavelengths. In terms of their dimensions, lifetimes and physical conditions, there is indirect evidence that there is a relationship between the identity of spicules and BPs of the chromospheric network, which can be attributed to the position of the magnetic field around the points. BPs form smaller or larger groups that, due to their specific morphology, carry plasma flux tubes to the magnetic corona. The flow behavior along BPs and spikes is a debatable issue. However, observations of the contents of the sticks show periodic up and down movements. In this research, using images of the solar disc extracted by the IRIS space telescope, we investigate the periodic behavior of fast brightening on a small scale. By analyzing the movements of these points using the wavelet method, one can understand their periodicity. Examining these points in wavelengths of 1400, 1330, 2796 Å to the real identity and the effect of these points on the reactions obtained by the sun. The bright points of the grid are arranged for the light grains visible in the filters and in the roughly cellular designs that form the boundaries of the grid. According to the graphs of wavelet analysis, the three-minute peaks are quite clear. The 3-minute and 5-minute chromospheric peaks seen in these analyzes show that the considered bright points are P modes, which means compression mode. In the three-minute oscillations, the origin is chromospheric, and in the five-minute oscillations, the origin is photosphere. Origin of the p modes is (5-minute fluctuations) compressive forces. Spectral images were used to obtain Doppler velocities and these velocities were calculated as -20  to 30 km-1. The results of this study suggested that these bright points are short-lived sources of plasma that originate from the chromosphere or the lower atmosphere of the Sun.

Chromosphere is the second layer of the Sun with high variability. The increase of the temperature and the decrease of the density are observed in this layer. This unusual behavior is one of the most important problems in the solar corona. Between the solar chromosphere and the corona, there is a thin transition zone in which the temperature rises very rapidly. Magnetohydrodynamic waves are thought to play an important role in this heating. The dissipation of Alfven waves has been investigated due to phase mixing in the presence of steady flow and sheared magnetic field in a solar stratified flux tube. The temperature variations with height (T0(z)) in the flux tube has been considered. The numerical calculations showed that the amplitude of the tube oscillations decreases with time. Hence, the wave damping takes place in the flux tubes. The temperature and the density variations enhances the wave damping rate compared to the case without temperature effect.

In this paper, a spectral approach to the origin and propagation of magnetoacoustic oscillations in the network and internetwork areas of solar granules is performed. The data used in this study are mostly from Interface Region Imaging Spectrometer (IRIS). Slit Jaw Images (SJIs) data of IRIS at wavelengths of 1400 angstroms related to Si IV and 2796 angstroms related to Mg II h / k and 2832 angstroms related to Mg II w s, are used to select network and internetwork areas. The data of the Mg II k spectrum with a wavelength of 2796 angstroms and a temperature of 10, 000 Kelvin have been used to construct the temporal profile of the intensity at the peaks of h3, k3, h2r, h2v, k2r and k2v, and the prospective profile of intensity temperature. One of the common methods for temporal and frequential characteristics analysis is the use of wavelet analysis. This method seems to be a practical method due to the variety and flexibility of wavelet types for different types of analysis. Wavelets and their convolution with waves lead to the extraction of time, frequency and power data. It should be noted that due to the uncertainty principle, resolution of time and frequency interact and its need to select optimum limit of the time and frequency resolution. One of the reasons for choosing Morlet Wavelet for the analysis of this study is the lack of a sharp edge, which reduces the ripple and improves the accuracy of detect the fluctuations properties. Another and one of the most important reasons for using the Morlet wavelet is that it does not change the temporal resolution of the wave. For these reasons, Morlett 5 was the most sensible and reliable choice for high-temporal and frequency-specific results for this study. Using wavelet analysis, the oscillation characteristics of the intensity are obtained in the network areas and internetwork areas. By Investigation of the intensity profiles in h and k peaks, it was found that the general behavior in them was the same and the only difference was in the intensities of these peaks and therefore their temperatures. In the case of intensity temperature profiles, the general behavior for intensity temperature profiles extracted from h and k peaks, also seems to be the same. By investigation of the wavelet analysis results, it appears that the oscillating behavior at the h and k peaks is almost similar. Using the results of wavelet analysis, in this study, the periods of oscillations in the intensities of bright points in the network and internetwork have been obtained. According to their values, it seems that the bright points of the internetwork have a photospheric origin and the bright points of the network have a chromospheric origin. Another result of the wavelet analysis of this study was the intensity of oscillations with a period of about 64 seconds. This high frequency differs from the solar researchers’ observations of photosphere and chromosphere oscillations, so it cannot be related to those oscillations. It seems that this is the first time that this type of high frequency oscillations has been reported. It seems that these high frequency oscillations can play an important role in heating the TR. For this reason, Accurate study of these high frequency oscillations is necessary to understand the causes and heating mechanisms of TR. These high frequency oscillations have been seen in almost all data and areas under study, so far there is no strong evidence of the origin and cause of these high frequency oscillations, and we hope that with more detailed and extensive studies we can better understand the properties and reason of these oscillations.

The mechanism of wave dissipation in different layers of the sun, as well as the solar granules inter-network bright points and internetwork bright points of chromosphoric solar granules, have been explored in this article. This article's data come from the Interface Region Imaging Spectrograph (IRIS). IRIS is a small exploration mission by NASA. That obtains spectra in near-ultraviolet (NUV), far-ultraviolet 1 (FUV1), and far-ultraviolet 2 (FUV2), from 1332 to 2834 . Slit jaw images (SJIs) of IRIS, using various filters that can provide images centered on the Mg II h wing, Mg II k, Si IV 1403 , and C ii lines. To begin, bright points in the chromosphere are selected for this goal. These points were first chosen using IRIS Slit Jaw Images (SJI) Si IV 1403 . The time slices of the Doppler velocity of the Mg II k spectrum are then drawn at a specified velocity (+/- 20 km/s) and were fed into the wavelet transform function to perform the time-frequency analysis to obtain the oscillation periods of the Doppler velocity. The wavelet transform used for this purpose is Morlet 5 wavelet. The velocity oscillation period data are utilized to determine the bright points of the network and internetwork solar granules at the chromosphere. The Doppler shift diagram for the Si IV 1394 spectral line is then displayed in time. This graph is a Doppler shift various time graph with attenuation that is caused by wave loss in the solar layers. According to the obtained data, the network and internetwork bright points, the chromospheric solar granules have an attenuation time 3 to 5 min. The oscillations of the solar granules network bright points are damped more intensely than the solar granules inter-network bright points, and hence their damping lifetime is shorter. Si IV 1394  Doppler velocity shift of bright points placed in the solar granules inter-network is dampened by a lower slope and so has a longer damping life time. Sadeghi and Tavabi researched about the kinetic energy above the bright points of the network and internetwork regions of the solar granules in a part of a paper titled "A new approach to kinetic energy flux at the different frequencies above the IRIS bright points" in 2022. They claim that a substantial percentage of the energy of the network bright points of solar granules is transferred to higher layers, namely the transition region corona, in the network bright points of solar granules. These findings are congruent with the findings of the current study. The oscillations in these locations are dampened for a brief period of time, and the energy is transmitted to higher layers with little loss. Furthermore, it is stated in the cited paper that the majority of the energy at the internetwork bright points of the solar granules does not transfer to higher layers of Sun. This suggests that the energy loss from bright points in the solar granules' internetwork region is rather high in the chromospheric layer. The time period of the wave damping is longer than the length of the damping time in the oscillations, according to the current study on the mechanism of wave dissipation in different layers of the sun and the network and internetwork bright points of the chromosphere. It has also been demonstrated that the time period of the wave damping is greater than the length of the damping time in the oscillations of the bright points of the granules' network region, which is the source of the most energy loss in this layer.