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The Martian hydrogen exosphere extends out of the bow shock, forming a "hydrogen corona". The solar wind interacts directly with the hydrogen corona. During an ICME event on 7 March 2015, the SWIA instrument onboard Mars Atmosphere and Volatile Evolution mission (MAVEN) observed that the pick-up H+ fluxes in upstream solar wind were enhanced. Also increased were the penetrating H+ fluxes in the Martian atmosphere. Quantitatively, these penetrating H+ fluxes cannot increase by a factor of 5 simply due to a factor of 3 increase in the solar wind density, suggesting that the increased abundance of exospheric hydrogen upstream of the bow shock was a consequence of the passage of the ICME. A denser outer hydrogen corona at high altitudes suggests that the expansion of the neutral atmosphere was caused by the ICME. The excited and heated hydrogen exosphere probably indicates an elevated hydrogen escape rate during an ICME.

We perform a statistical analysis of data from the Mars Atmosphere and Volatile Evolution (MAVEN) project on the global distribution of protons in the Martian magnetosheath. Our results show that the proton number density distribution has a south-north asymmetry. This south-north asymmetry is most likely caused by the south-north asymmetric distributions of the crustal magnetic fields at Mars. The strong crustal magnetic fields push the inner boundary of magnetosheath to a higher altitude in the southern hemisphere. Due to the outward movement of the inner boundary of the magnetosheath, a compressed magnetosheath forms, causing subsequent increases in proton number density, thermal pressure, and total pressure. Eventually, a balance is reached between the increased total pressure inside the magnetosheath and the increased magnetic pressure inside the induced magnetosphere. Our statistical study suggests that the Martian crustal magnetic fields can strongly affect the proton number density distribution in the Martian magnetosheath.

Source MAVEN data for figure 2 - 4

The evolution of magnetic helicity has a close relationship with solar eruptions and is of interest as a predictive diagnostic. In this case study, we analyse the evolution of the normalised emergence, shearing and total magnetic helicity components in the case of three flaring and three non-flaring active regions (ARs) using SHARPs (Spaceweather Helioseismic Magnetic Imager Active Region Patches) vector magnetic field data. The evolution of the three magnetic helicity components is analysed with wavelet transforms, revealing significant common periodicities of the normalised emergence, shearing and total helicity fluxes before flares in the flaring ARs. The three non-flaring ARs do not show such common periodic behaviour. This case study suggests that the presence of significant periodicities in the power spectrum of magnetic helicity components could serve as a valuable precursor for flares.

Using the data from the Advanced Composition Explorer (ACE) and Wind spacecraft, we statistically studied the Parker spiral angle (PSA) of the solar wind magnetic field from 1998 to 2019 at 1 au. The PSA occurrences over both a Carrington rotation (CR) and a year can be well fitted by a Gaussian distribution. However, large-scale magnetic structures, such as interplanetary coronal mass ejections (ICMEs), can significantly deviate the PSA distribution of a CR from the Gaussian distribution. The PSA distributions of each CR and each year are affected by the solar activity: They are more concentrated at a relatively higher average PSA at solar maximum. There is also a weak anticorrelation between the yearly solar wind speed (v sw) and the average PSA. MESSENGER, Venus Express, and ACE observations at different heliocentric distances within 1 au show that the dominating polarities of the heliospheric magnetic field change greatly from year to year even when the solar activity is on the same level. Our results suggest that the PSA distribution in addition to the sunspot number can provide some new information on the magnetic field variation of the Sun.

The influences of the interplanetary magnetic field (IMF) on the induced magnetosphere of Venus are investigated using a global multispecies magnetohydrodynamics (MHD) model. The simulation results show that the induced magnetosphere is controlled by the IMF components perpendicular to the solar wind velocity (B Y and B Z in the Venus Solar Orbital coordinate), rather than the IMF magnitude (∣B∣). With the increase of ( B Y 2 + B Z 2 ) 1 2 , the induced magnetosphere becomes stronger in field strength and thicker in spatial scale, and the bow shock locates farther from the planet. The parallel IMF component (B X ) has relatively small impacts on the magnetic barrier and the magnetotail, regardless of the various IMF magnitudes and orientations caused by different B X . The responses of the Venusian induced magnetosphere to the change of upstream IMF are also studied. The time-dependent MHD calculations show that the dayside magnetosphere responds quickly with a timescale of 10 s–10 minutes, depending on the considered magnetospheric region. For comparison, the timescale required for the adjustment of magnetotail as driven by an IMF rotation is derived to be ∼10–20 minutes.

Plasma heating at thin current sheets in the solar wind is examined using magnetic field and plasma data obtained by the WIND spacecraft in the past 17 years from 2004 to 2019. In this study, a thin current sheet is defined by an abrupt rotation (larger than 45°) of the magnetic field direction in 3 s. A total of 57,814 current sheets have been identified, among which 25,018 current sheets are located in the slow wind and 19,842 current sheets are located in the fast wind. Significant plasma heating is found at current sheets in both slow and fast wind. Proton temperature increases more significantly at current sheets in the fast wind than in the slow wind, while the enhancement in electron temperature is less remarkable at current sheets in the fast wind. The results reveal that plasma heating commonly exists at thin current sheets in the solar wind regardless of the wind speed, but the underlying heating mechanisms might be different.

We present a combined analysis of the applications of the weighted horizontal magnetic gradient (denoted as WG M in Korsos et al. (2015)) method and the magnetic helicity tool (Berger and Field, 1984) employed for three active regions (ARs), namely NOAA AR 11261, AR 11283 and AR 11429. We analysed the time series of photospheric data from the Solar Dynamics Observatory taken between August 2011 and March 2012. During this period the three ARs produced a series of flares (eight M- and six X-class) and coronal mass ejections (CMEs). AR 11261 had four M-class flares and one of them was accompanied by a fast CME. AR 11283 had similar activities with two M- and two X-class flares, but only with a slow CME. Finally, AR 11429 was the most powerful of the three ARs as it hosted five compact and large solar flare and CME eruptions. For applying the WG M method we employed the Debrecen sunspot data catalogue, and, for estimating the magnetic helicity at photospheric level we used the Space-weather HMI Active Region Patches (SHARP’s) vector magnetograms from SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager). We followed the evolution of the components of the WG M and the magnetic helicity before the flare and CME occurrences. We found a unique and mutually shared behaviour, called the U-shaped pattern, of the weighted distance component of WG M and of the shearing component of the helicity flux before the flare and CME eruptions. This common pattern is associated with the decreasing-receding phases yet reported only known to be a necessary feature prior to solar flare eruption(s) but found now at the same time in the evolution of the shearing helicity flux. This result leads to the conclusions that (i) the shearing motion of photospheric magnetic field may be a key driver for solar eruption in addition to the flux emerging process, and that (ii) the found decreasing-approaching pattern in the evolution of shearing helicity flux may be another precursor indicator for improving the forecasting of solar eruptions.

Background Chondrosarcoma(ChSa) is a rare malignant tumor. But it’s necessary to discuss the clinical characteristics and treatments for ChSa of paranasal sinus and the skull base.We aimed to Observe the effect of Endoscopic surgical treatment with nasal cavity approach for chondrosarcoma of paranasal sinus and the skull base Methods The clinical characteristics of chondrosarcoma of paranasal sinus and skull base in 10 patients (6 males and 4 females) from 2001 to 2017 were analyzed. They all underwent by endoscopic surgery. The patients’ age ranged from 18 to 47 years, with a median of 35 years. Clinical symptoms: stuffy, nose bleeding, runny, headache, diplopia, eye outreach limited, blurred vision and even blindness. Surgery methods：under nasal endoscopy, after the attachment sites of the tumors to normal tissues were confirmed, the tumors were peeled off along the clear boundary between the tumors and normal tissues, and the potential residual tumor tissues on bones were cleared by a drill. If internal carotid artery (ICA) were involved, flap would be used to protect it. Objectives Results All patients were treated with endoscopic surgery，followed up postoperatively for 24 to 108 months, with a median of 36 months. 8 of 10 patients were no recurrence,2 were alive with tumor. Conclusion Chondrosarcoma of paranasal sinus and skull base can be treated by nasal endoscopic surgery with good clinical results.

The Epstein-Barr virus (EBV) is tightly associated with a variety of human tumors, including Burkitt lymphoma and acquired immune deficiency syndrome-related lymphoma of B-cell origin, as well as nasopharyngeal carcinoma and gastric cancer of epithelial origin. The virus latently infects the host cells and expresses proteins and non-coding RNAs to achieve malignancy. MicroRNAs (miRNAs or miRs) are small RNAs consisting of 19–25 nucleotides, which directly bind to the 3′-untranslated region of mRNAs to promote degradation and inhibit translation of mRNAs. EBV-encoded miRs are generated from two regions of the viral genome, within the apoptosis regulator BHRF1 gene locus and near the BamHI A region in a latency type-dependent manner. In addition, EBV-encoded miRs epigenetically regulate the expression of molecules that are effectors of the cell cycle progression, migration, apoptosis and innate immunity, serving a vital role in supporting viral replication and occurrence of EBV-associated tumors. The feasibility of using such miRs as biomarkers for the diagnosis and prognosis of EBV-associated tumors is currently under investigation.

The Venusian plasma environment is divided into two distinct regions by the induced magnetosphere boundary (IMB): the domain of solar wind protons and the domain of local planetary ions. Previous studies on the identification of the IMB gave various IMB definitions. Here we study the well-structured Venusian IMB with a sudden magnetic field rotation and a sharp magnetosheath plasma decrease using Venus Express observations. We statistically investigate the location of such well-structured IMB and give an average location of the IMB at solar maximum. The solar activity and solar wind controls of the Venusian IMB location is also studied in this work. Our results show that the dayside Venusian IMB distance increases with solar activity, but it decreases with increasing solar wind dynamic pressure and interplanetary magnetic field cone angle. The behaviors of the IMB under these conditions are similar to those of the ionopause, indicating that the distance of the Venusian IMB is much correlated with the scale of the ionosphere. We suggest that the variation of the IMB is partially contributed to by the variation of the ionopause, whose altitude is determined by the pressure balance between ionospheric thermal pressure and external magnetic pressure.

The existence of small-scale plasmoids associated with the Hall effect has been often observed in the magnetotail. They are considered as the signature of multiple X-line collisionless reconnection. To study these plasmoids structures, we present some Cluster observations and Hall MHD simulations of their features. In this study, the observation survey is divided into two types. The first one is the isolated plasmoid with two typical plasmoid events the flux-rope-like plasmoid on 3 August 2001 and the closed-loop-like plasmoid on 22 August 2001. The second type contains multiple successive plasmoids, on 12 September 2001 with three neighboring plasmoids structures observed during a substorm. Especially for the second plasmoid, three main features were observed, including a core field in the plasmoid, a quadrupole magnetic field near the X line, and a local plasma convection within the plasmoid. The Grad-Shafranov reconstruction method was used to recover the two-dimensional magnetic field maps for this plasmoid. These results may provide evidence that the small-scale plasmoids frequently observed in the magnetotail may be produced by multiple X-line collisionless reconnection. To study the impact of crosstail magnetic field on the structures of small-scale plasmoids, a 2.5-D Hall MHD simulation was performed. In the case with a guide field By0, the in-plane plasma inflows carrying Byflux enter into the plasmoid due to magnetic reconnection. However, there is no such By flux transport process for the case without guide field. These results demonstrate that a crosstail magnetic field is an important factor in the formation of flux-rope-like plasmoids.

Coronal Mass Ejections (CMEs) are arguably the most violent eruptions in the Solar System. CMEs can cause severe disturbances in the interplanetary space and even affect human activities in many respects, causing damages to infrastructure and losses of revenue. Fast and accurate prediction of CME arrival time is then vital to minimize the disruption CMEs may cause when interacting with geospace. In this paper, we propose a new approach for partial-/full-halo CME Arrival Time Prediction Using Machine learning Algorithms (CAT-PUMA). Via detailed analysis of the CME features and solar wind parameters, we build a prediction engine taking advantage of 182 previously observed geo-effective partial-/full-halo CMEs and using algorithms of the Support Vector Machine (SVM). We demonstrate that CAT-PUMA is accurate and fast. In particular, predictions after applying CAT-PUMA to a test set, that is unknown to the engine, show a mean absolute prediction error $\sim$5.9 hours of the CME arrival time, with 54% of the predictions having absolute errors less than 5.9 hours. Comparison with other models reveals that CAT-PUMA has a more accurate prediction for 77% of the events investigated; and can be carried out very fast, i.e. within minutes after providing the necessary input parameters of a CME. A practical guide containing the CAT-PUMA engine and the source code of two examples are available in the Appendix, allowing the community to perform their own applications for prediction using CAT-PUMA., 13 pages, 7 figures, 2 tables; accepted by the Astrophysical Journal

To assess the long-term clinical efficacy of endoscopic surgery of primary sinonasal malignant neoplasms and find out the potential postoperative prognostic factors.Forty-three clinical cases of primary sinonasal malignant neoplasms treated under endoscopy were analyzed retrospectively.Fifteen patients died. The 1-year, 2-year, 3-year and 5-year survival rates were 83. 7% (36/43), 74. 4% (32/43), 69. 8% (30/43) and 65. 1% (28/43), respectively. Kaplan-Meier single-variable analysis showed that gender, T grade, TNM stage and pathological types of olfactory neuroblastoma were statistically significant prognostic factors (P0. 05). COX Pro-Portional hazard models showed that TNM stage was an independent prognostic factors.Endoscopic surgery for primary sinonasal malignant neoplasms is a safe and effective minimally invasive surgical treatment, and it is an important supplement to the traditional surgery. Gender, T grade, TNM stage and pathological types of olfactory neuroblastoma might be significant prognostic factors.