Real-Time Equilibrium Reconstruction in a Tokamak

This paper deals with the numerical reconstruction of the plasma current density in a Tokamak and of its equilibrium. The problem consists in the identification of a non-linear source in the 2D Grad-Shafranov equation, which governs the axisymmetric equilibrium of a plasma in a Tokamak. The experimental measurements that enable this identification are the magnetics on the vacuum vessel, but also polarimetric and interferometric measures on several chords, as well as motional Stark effect or pressure measurements. The reconstruction can be obtained in real-time using a finite element method, a non-linear fixed-point algorithm and a least-square optimization procedure

Thyroid function, autoimmunity and nodules in hematological malignancies

Objective Hematological malignancies encompass a large spectrum of disease entities whose treatment by chemo/radiotherapy could lead to thyroid complications. To the best of our knowledge, no study has simultaneously addressed thyroid function, autoimmunity and nodularity. Therefore, we decided to conduct one.Materials and methods We evaluated 82 Caucasian patients (36 women and 46 men), who were treated at our Oncology division for hematological malignancies (multiple myeloma, chronic myeloid leukemia, chronic lymphatic leukemia, non-Hodgkin lymphoma and polycythemia vera) and compared them with a control group of 104 patients. Patients who had received or were receiving external head/neck radiotherapy were excluded. All oncological patients and control individuals underwent thyroid ultrasonography and thyroid function and autoimmunity tests.Results A lower prevalence of enlarged thyroid and nodules were found in patients with respect to controls. The rate of thyroid nodules was the highest in multiple myeloma and polycythemia vera, and the lowest in chronic lymphatic leukemia. Non-Hodgkin lymphoma patients had the smallest thyroid nodules while men with multiple myeloma the biggest ones. No patient had hypothyroidism, while 5.6% of patients had subclinical hyperthyroidism. In contrast, within the control group the rates of hypothyroidism and hyperthyroidism, overt and subclinical, were 3.8%, 20.2%, 0% and 0% respectively. Moreover, the overall rate of thyroid autoantibody positiveness in patients was significantly lower than controls.Conclusion In our experience, we found a significantly lower prevalence of thyroid abnormalities in hematologic patients who underwent chemotherapy, but not radiotherapy, with respect to controls. Arch Endocrinol Metab. 2015;59(3):236-4

Search for hydrogen peroxide in the Martian atmosphere by the Planetary Fourier Spectrometer onboard Mars Express

We searched for hydrogen peroxide (H2O2) in the Martian atmosphere using data measured by the Planetary Fourier Spectrometer (PFS) onboard Mars Express during five martian years (MY27-31). It is well known that H2O2 plays a key role in the oxidizing capacity of the Martian atmosphere. However, only a few studies based on ground-based observations can be found in the literature. Here, we performed the first analysis of H2O2 using long-term measurements by a spacecraft-borne instrument. We used the ν4 band of H2O2 in the spectral range between 359 cm-1 and 382 cm-1 where strong features of H2O2 are present around 362 cm-1 and 379 cm-1. Since the features were expected to be very weak even at the strong band, sensitive data calibrations were performed and a large number of spectra were selected and averaged. We made three averaged spectra for different seasons over relatively low latitudes (50°S-50°N). We found features of H2O2 at 379 cm-1, whereas no clear features were detected at 362 cm-1 due to large amounts of uncertainty in the data. The derived mixing ratios of H2O2 were close to the detection limits: 16 ± 19 ppb at Ls = 0-120°, 35 ± 32 ppb at Ls = 120-240°, and 41 ± 28 ppb at Ls = 240-360°. The retrieved value showed the detection of H2O2 only for the third seasonal period, and the values in the other periods provided the upper limits. These long-term averaged abundances derived by the PFS generally agreed with the ones reported by ground-based observations. From our derived mixing ratio of H2O2, the lifetime of CH4 in the Martian atmosphere is estimated to be several decades in the shortest case. Our results and sporadic detections of CH4 suggest the presence of strong CH4 sinks not subject to atmospheric oxidation. <P /

Seasonal variation of the HDO/H2O ratio in the atmosphere of Mars at the middle of northern spring and beginning of northern summer

We present the seasonal variation of the HDO/H2O ratio caused by sublimation-condensation processes in a global view of the martian water cycle. The HDO/H2O ratio was retrieved from ground-based observations using high-dispersion echelle spectroscopy of the Infrared Camera and Spectrograph (IRCS) of the Subaru telescope. Coordinated joint observations were made by the Planetary Fourier Spectrometer (PFS) onboard Mars Express (MEX). The observations were performed during the middle of northern spring (Ls = 52°) and at the beginning of summer (Ls = 96°) in Mars Year 31. The retrieved latitudinal mean HDO/H2O ratios are 4.1 ± 1.4 (Ls = 52°) and 4.4 ± 1.0 (Ls = 96°) times larger than the terrestrial Vienna Standard Mean Ocean Water (VSMOW). The HDO/H2O ratio shows a large seasonal variation at high latitudes. The HDO/H2O ratio significantly increases from 2.4 ± 0.6 wrt VSMOW at Ls = 52° to 5.5 ± 1.1 wrt VSMOW at Ls = 96° over the latitude range between 70°N and 80°N. This can be explained by preferential condensation of HDO vapor during the northern fall, winter, and spring and sublimation of the seasonal polar cap in the northern summer. In addition, we investigated the geographical distribution of the HDO/H2O ratio over low latitudes at the northern spring in the longitudinal range between 220°W and 360°W, including different local times from 10 h to 17 h. We found the HDO/H2O ratio has no significant variation (5.1 ± 1.2 wrt VSMOW) over the entire range. Our observations suggest that the HDO/H2O distribution in the northern spring and summer seasons is mainly controlled by condensation-induced fractionation between the seasonal northern polar cap and the atmosphere

Preliminary estimation of the detection possibilities of Ganymede's water vapor environment with MAJIS

The exosphere of Ganymede is the interface region linking the moon's icy surface to Jupiter's magnetospheric environment. Its characterization is of key importance to achieve a full understanding of the ice alteration processes induced by the radiation environment. Several scientific instruments that will operate on board the upcoming Jupiter Icy Moons Explorer (JUICE) mission, selected by ESA in the context of its Cosmic Vision programme, have the potential to study Ganymede's exosphere. Among them, the Moons And Jupiter Imaging Spectrometer (MAJIS) will have the chance to investigate the composition of the moon's exospheric components and the emission of water molecules. The exospheric water density profile, as obtained from current models, is a crucial parameter for the estimation of the expected signal to noise ratio related to the actual measurement. In lack of an adequate number of Ganymede's observations from past missions, there is a general difficulty in constraining current exosphere models which are based, in general, on different scenarios and considerations and often show large discrepancies in the estimated spatial distribution of the neutral environment. In this work, we make a preliminary estimation of the expected IR emission from exospheric water molecules, using different modelled density profiles, and we speculate on the possibility of JUICE/MAJIS to detect it. An exercise on the potential plume detection capabilities of MAJIS is also performed. The first necessary step for performing these calculations is a rough comparison of the existing models of Ganymede's water vapor exosphere. We discuss the characteristics of the neutral environment as derived from different exospheric models available in literature, the role of the ion-surface interactions in the H2O exosphere generation, and the related implications also in view of future observations. We then use the model outputs to estimate different scenarios for the expected non-Local Thermal Equilibrium (non-LTE) emission from these molecules. The results of this study can be of help during the JUICE observation planning phase

CAESAR: Space Weather archive prototype for ASPIS

The project CAESAR (Comprehensive spAce wEather Studies for the ASPIS prototype Realization) is aimed to tackle all the relevant aspects of Space Weather (SWE) and realize the prototype of the scientific data centre for Space Weather of the Italian Space Agency (ASI) called ASPIS (ASI SPace Weather InfraStructure). This contribution is meant to bring attention upon the first steps in the development of the CAESAR prototype for ASPIS and will focus on the activities of the Node 2000 of CAESAR, the set of Work Packages dedicated to the technical design and implementation of the CAESAR ASPIS archive prototype. The product specifications of the intended resources that will form the archive, functional and system requirements gathered as first steps to seed the design of the prototype infrastructure, and evaluation of existing frameworks, tools and standards, will be presented as well as the status of the project in its initial stage.Comment: 4 pages, 2 figures, ADASS XXXII (2022) Proceeding

Vorticity and divergence at scales down to 200 km within and around the polar cyclones of Jupiter

Since 2017 the Juno spacecraft has observed a cyclone at the north pole of Jupiter surrounded by eight smaller cyclones arranged in a polygonal pattern. It is not clear why this configuration is so stable or how it is maintained. Here we use a time series of images obtained by the JIRAM mapping spectrometer on Juno to track the winds and measure the vorticity and horizontal divergence within and around the polar cyclone and two of the circumpolar ones. We find an anticyclonic ring between the polar cyclone and the surrounding cyclones, supporting the theory that such shielding is needed for the stability of the polygonal pattern. However, even at the smallest spatial scale (180 km) we do not find the expected signature of convection—a spatial correlation between divergence and anticyclonic vorticity—in contrast with a previous study using additional assumptions about the dynamics, which shows the correlation at scales from 20 to 200 km. We suggest that a smaller size, relative to atmospheric thickness, of Jupiter’s convective storms compared with Earth’s, can reconcile the two studies

Ganymede as Observed by JIRAM During the Juno Flyby of 7 June 2021

Since Juno's orbit insertion at Jupiter until today, the JIRAM spectro-imager observed Ganymede over 5000 times, both with its infrared imaging subsystem and with its slit spectrometer sensitive to the 2-5 µm spectral range. This dataset makes Ganymede the most observed Galilean satellite by Juno. Towards the end of 2019, during perijove 24, JIRAM achieved a maximum spatial resolution of 23 km/px. But during the latest flyby, which occurred on June 7, 2021, during perijove 34, JIRAM observed Ganymede from a much shorter distance, namely between 1053 and 2558 km from the surface, yielding unprecedented pixel resolution values between 0.25 and 0.61 km/px (average value 0.36 km/px), which is 92 times better than the previous flyby and 3 to 7 times better than the most resolved hyperspectral image ever acquired in the past by the Galileo/NIMS instrument at Ganymede. Here we discuss the infrared images and spectra that JIRAM was able to acquire during this flyby, with an emphasis on the preliminary spectroscopic results and the distribution of the chemical species detectable in the spectra. These results are important also in preparation for future measurements to be returned by the ESA JUICE mission, which aims to achieve near-global coverage of Ganymede in the 2030s. Acknowledgements: JIRAM is funded by the Italian Space Agency (ASI), ASI-INAF contract 2016-23-H.0. The JIRAM instrument was built by Selex ES, under the leadership of the Italian National Institute for Astrophysics, Institute for Space Astrophysics and Planetology (INAF-IAPS), Rome, Italy. JIRAM is operated by INAF-IAPS, Rome, Italy. Support of the Juno Science and Operations Teams is gratefully acknowledged