The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MIN...The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MINPA was switched on to measure the solar wind ions.Here,we present the first results of the MINPA observations in the solar wind.During cruise,nearly half of the MINPA ion field-of-view(FOV)was blocked by the lander capsule;thus only the solar-wind ions with azimuthal speeds pointing towards the unblocked FOV sectors could be detected.We perform a detailed comparison of the MINPA’s solar wind observations with data from Earth-based missions when MINPA reached its count-rate peak,finding a general consistency of the ion moments between them.The blocking effect due to the lander is evaluated quantitatively under varying solar-wind velocity conditions.Despite the blocking effect,the MINPA’s solar wind measurements during the transfer orbit suggest a good performance.展开更多
Unlike Earth,Mars lacks a global dipolar magnetic field but is dominated by patches of a remnant crustal magnetic field.In 2021,the Chinese Mars Rover will land on the surface of Mars and measure the surface magnetic ...Unlike Earth,Mars lacks a global dipolar magnetic field but is dominated by patches of a remnant crustal magnetic field.In 2021,the Chinese Mars Rover will land on the surface of Mars and measure the surface magnetic field along a moving path within the possible landing region of 20°W-50°W,20°N-30°N.One scientific target of the Rover is to monitor the variation in surface remnant magnetic fields and reveal the source of the ionospheric current.An accurate local crustal field model is thus considered necessary as a field reference.Here we establish a local crust field model for the candidate landing site based on the joint magnetic field data set from Mars Global Explorer(MGS)and Mars Atmosphere and Volatile Evolution(MAVEN)data combined.The model is composed of 1,296 dipoles,which are set on three layers but at different buried depths.The application of the dipole model to the joint data set allowed us to calculate the optimal parameters of their dipoles.The calculated results demonstrate that our model has less fitting error than two other state-of-the art global crustal field models,which would indicate a more reasonable assessment of the surface crustal field from our model.展开更多
Proton cyclotron waves(PCWs)can be generated by ion pickup of Martian exospheric particles in the solar wind.The solar wind ion pickup process is highly dependent on the“IMF cone angle”—the angle between the solar ...Proton cyclotron waves(PCWs)can be generated by ion pickup of Martian exospheric particles in the solar wind.The solar wind ion pickup process is highly dependent on the“IMF cone angle”—the angle between the solar wind velocity and the interplanetary magnetic field(IMF),which also plays an important role in the generation of PCWs.Using data from 2.15 Martian years of magnetic field measurements collected by the Mars Atmosphere and Volatile Evolution(MAVEN)mission,we have identified 3307 upstream PCW events.Their event number distribution decreases exponentially with their duration.A statistical investigation of the effects of IMF cone angle on the amplitudes and occurrence rates of PCWs reveals a slight tendency of PCWs’amplitudes to decrease with increasing IMF cone angle.The relationship between the amplitude and IMF cone angle is weak,with a correlation coefficient r=–0.3.We also investigated the influence of IMF cone angle on the occurrence rate of PCWs and found that their occurrence rate is particularly high for intermediate IMF cone angles(~18°–42°)even though highly oblique IMF orientation occurs most frequently in the upstream region of the Martian bow shock.We also conclude that these variabilities are not artefacts of temporal coverage biases in MAVEN sampling.Our results demonstrate that whereas IMF cone angle strongly influences the occurrence of PCWs,IMF cone angle may also weakly modulate their amplitudes in the upstream region of Mars.展开更多
The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exospher...The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exosphere,ionosphere,and magnetosphere,from both observational and modeling points of view.Due to the similarity between the two objects,the issue also includes two additional papers on the near-Venus plasma environment.展开更多
The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that t...The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that the expansion of the ionosphere may be strongly controlled by the EUV level, as exhibited in data collected by the Pioneer Venus Orbiter (PVO) during one solar cycle (1978 1992). However, the EUV-dependence of the Venusian dayside ionopause altitude, which defines the outer boundary of the ionosphere, remains obscure because the PVO crossed the dayside ionopause only during the solar maximum;its periapsis lifted too high during the solar minimum. Recently, during the period 2006 2014, which included the longest and quietest solar minimum of the past several decades, Venus Express (VEX) provided measurements of the photoelectron boundary (PEB) over the northern high-latitude region. Since the photoelectron boundary is closely related to the ionopause, we have an opportunity to analyze the EUV effect on the dayside ionopause by combining PVO and VEX observations. We have evaluated and then reduced the orbit bias effect in data from both PVO and VEX, and then used the results to derive a relationship between solar EUV level and the dayside ionopause altitude. We find that the dayside ionopause altitude increases as the solar EUV level increases, which is consistent with theoretical expectations.展开更多
The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior ...The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior process is contentious. In the past several decades,space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate(>5 ka). Here, we propose to take the advantage of " space-diversity" to build a " generalized planetary space family", to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets' evolution.展开更多
The strength and configuration of the geomagnetic field control the average shape of the magnetosphere.The pure dipole assumption and the virtual dipole moment(VDM),determined by individual records,have been widely ad...The strength and configuration of the geomagnetic field control the average shape of the magnetosphere.The pure dipole assumption and the virtual dipole moment(VDM),determined by individual records,have been widely adopted to evaluate the strength of the geomagnetic field in geological time.However,such an assumption might not be valid during geomagnetic transitions,such as reversals and excursions.The traditional spherical harmonic modeling of the geomagnetic field could be difficult to implement because accurate global records are lacking.Here,we report that an empirical relationship exists between the ratio of the VDM to the true axial dipole moment(VDM/ADM)and the ratio of the power of the axial dipole to that of the non-axial dipole(AD/NAD)based on a new method utilizing globally distributed inclination records.The root mean square global deviation of inclination(RMSΔI)to the standard inclination distribution of the AD was fitted to the AD/NAD with a cubic polynomial by utilizing a large number of geodynamo simulations.Tests with geomagnetic field models showed that the AD/NAD derived from the RMSΔI agreed well with that calculated by using the Gauss coefficients,and the estimated ADM was consistent with the true value.Finally,the application of volcanic records during the Laschamp excursion showed the VDM might overestimate the ADM by a factor of 3.Our new method will be useful in future studies that characterize the configuration of the geomagnetic field and the strength of the axial dipole.展开更多
The 5th Youth Scientist Forum of Planetary Science(YSFPS)took place from March 25 to 29,2023,in Sanya,a picturesque coastal city in the Hainan Province of southern China.This forum,one of China’s largest gatherings o...The 5th Youth Scientist Forum of Planetary Science(YSFPS)took place from March 25 to 29,2023,in Sanya,a picturesque coastal city in the Hainan Province of southern China.This forum,one of China’s largest gatherings of its kind,experienced over 1,000 participants from domestic universities and research institutes discussing advancements in a variety of topics,including the surface,atmosphere,interior,core of planets,exoplanet exploration,asteroids,and comets(as shown in Figure 1A).One of the international hot topics in this meeting was lunar science research.With the return of lunar samples from the Chang’e-5 mission,scientists have immediately carried out various studies,forming new understandings about the moon’s evolution and raising new questions.展开更多
On the great journey to Mars,China’s first planetary exploration mission,the Tianwen-1 came within 26 million kilometers of Mars from 31 October 2020 to 25 January 2021 and was getting closer to its destination,the r...On the great journey to Mars,China’s first planetary exploration mission,the Tianwen-1 came within 26 million kilometers of Mars from 31 October 2020 to 25 January 2021 and was getting closer to its destination,the red planet,in search of answers to the cataclysmic climate change that occurred in Martian history.Both the escape of the Martian atmosphere and the loss of surface water were firmly influenced by solar activities.Tianwen-1 provided a unique chance to depict the solar wind streams between Earth and Mars during the minimum of Solar Cycle 25.During the three-month cruise phase of Tianwen-1,the solar wind flows were successively observed at Earth,Tianwen-1,and Mars.After the field of view correction and noise reduction,the solar wind velocity and density measured by Tianwen-1 show good agreement with those at Earth and Mars.The results indicate that the performance of the ion analyzer onboard the Tianwen-1 orbiter is reliable and stable.It is worth looking forward to the joint observations of ion escape with other Mars probes in the following Martian years.展开更多
As an Earth-like planet Venus probably had a primordial dipole field for several million years after formation of the planet.Since this dipole field eventually vanished the ionosphere of Venus has been exposed to the ...As an Earth-like planet Venus probably had a primordial dipole field for several million years after formation of the planet.Since this dipole field eventually vanished the ionosphere of Venus has been exposed to the solar wind.The solar wind is shocked near Venus,and then scavenges the ionospheric particles through the magnetosheath and the magnetotail.The escape rate of oxygen ions(O^+)estimated from spacecraft observations over the past several decades has manifested its importance for the evolution of planetary habitability,considering the accumulated effect over the history of Venus.However,all the previous observations were made in the shocked solar wind and/or inside the wake,though some simulations showed that unshocked solar wind can also ablate O^+ions.Here we report Venus Express observations of O^+ions in the unshocked solar wind during the solar minimum.The observations suggest that these O^+ions are accelerated by the unshocked solar wind through pickup processes.The estimated O^+escape rate,2.1×10^(24) ions/s,is comparable to those measured in the shocked solar wind and the wake.This escape rate could result in about 2 cm global water loss over 4.5 billion years.Our results suggest that the atmospheric loss at unmagnetized planets is significantly underestimated by previous observations,and thus we can emphasize the importance of an Earth-like dipole for planetary habitability.展开更多
Extensive research efforts have revealed that the Martian dust storms can perturb the upper atmospheric condition and as a consequence,enhance plasma density and photoelectron flux in the ionosphere.However,previous o...Extensive research efforts have revealed that the Martian dust storms can perturb the upper atmospheric condition and as a consequence,enhance plasma density and photoelectron flux in the ionosphere.However,previous observational studies of the Martian dust storm impacts have been restricted to regions below 400 km,which limits our understanding of the Martian dust storm effects in the upper ionosphere and magnetosphere.Here,based on the suprathermal electron measurements made by the Solar Wind Electron Analyzer onboard the Mars Atmosphere and Volatile Evolution,we identify with an automatic procedure the occurrences of all photoelectron boundary(PEB)crossings at solar zenith angle below 120°(with a dust-free median altitude of about 600 km).Using the dayside PEB as a proxy of the upper ionospheric and magnetospheric condition,we analyze the variations of the PEB altitude during the 2018 global dust storm(GDS)of Mars Year 34(MY34)and compare them with the period in MY33 when there was no global dust storm.We conclude that the column dust optical depth(CDOD)emerges as one of the main driving factors for PEB altitude variations during the GDS.Our analysis implies that the GDS can affect the Martian upper atmosphere and ionosphere over considerable distances and extended time scales.展开更多
基金supported by the Key Research Program of the Chinese Academy of Sciences(Grant NO.ZDBS-SSW-TLC00103)Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB41000000)+3 种基金NNSFC Grant No.41974170 and 41974196Specialized Research Fund for State Key Laboratories of China,and Pandeng Program of National Space Science Center,Chinese Academy of Sciences.BBT(2019153),YTZ(2017186),WYL(2018177)LHX(2021144)were supported by the Youth Innovation Promotion Associationfunded by the Young Elite Scientists Sponsorship Program by CAST.
文摘The Mars Ion and Neutral Particle Analyzer(MINPA)is one of the three scientific instruments onboard the Tianwen-1 orbiter to investigate the Martian space environment.During Tianwen-1’s transfer orbit to Mars,the MINPA was switched on to measure the solar wind ions.Here,we present the first results of the MINPA observations in the solar wind.During cruise,nearly half of the MINPA ion field-of-view(FOV)was blocked by the lander capsule;thus only the solar-wind ions with azimuthal speeds pointing towards the unblocked FOV sectors could be detected.We perform a detailed comparison of the MINPA’s solar wind observations with data from Earth-based missions when MINPA reached its count-rate peak,finding a general consistency of the ion moments between them.The blocking effect due to the lander is evaluated quantitatively under varying solar-wind velocity conditions.Despite the blocking effect,the MINPA’s solar wind measurements during the transfer orbit suggest a good performance.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDA17010201)the National Natural Science Foundation of China(grants nos.41922031,41774188,41525016,and 41621063).
文摘Unlike Earth,Mars lacks a global dipolar magnetic field but is dominated by patches of a remnant crustal magnetic field.In 2021,the Chinese Mars Rover will land on the surface of Mars and measure the surface magnetic field along a moving path within the possible landing region of 20°W-50°W,20°N-30°N.One scientific target of the Rover is to monitor the variation in surface remnant magnetic fields and reveal the source of the ionospheric current.An accurate local crustal field model is thus considered necessary as a field reference.Here we establish a local crust field model for the candidate landing site based on the joint magnetic field data set from Mars Global Explorer(MGS)and Mars Atmosphere and Volatile Evolution(MAVEN)data combined.The model is composed of 1,296 dipoles,which are set on three layers but at different buried depths.The application of the dipole model to the joint data set allowed us to calculate the optimal parameters of their dipoles.The calculated results demonstrate that our model has less fitting error than two other state-of-the art global crustal field models,which would indicate a more reasonable assessment of the surface crustal field from our model.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No.XDA17010201)supported by Thousand Young Talents Program of China and Chinese NSFC grant (41525016, 41474155, 41661164034, 41621004, 41374180, 41774188)+1 种基金cofunded by EU. Asupported by the Fund for Scientific Research (F.R.S.FNRS)
文摘Proton cyclotron waves(PCWs)can be generated by ion pickup of Martian exospheric particles in the solar wind.The solar wind ion pickup process is highly dependent on the“IMF cone angle”—the angle between the solar wind velocity and the interplanetary magnetic field(IMF),which also plays an important role in the generation of PCWs.Using data from 2.15 Martian years of magnetic field measurements collected by the Mars Atmosphere and Volatile Evolution(MAVEN)mission,we have identified 3307 upstream PCW events.Their event number distribution decreases exponentially with their duration.A statistical investigation of the effects of IMF cone angle on the amplitudes and occurrence rates of PCWs reveals a slight tendency of PCWs’amplitudes to decrease with increasing IMF cone angle.The relationship between the amplitude and IMF cone angle is weak,with a correlation coefficient r=–0.3.We also investigated the influence of IMF cone angle on the occurrence rate of PCWs and found that their occurrence rate is particularly high for intermediate IMF cone angles(~18°–42°)even though highly oblique IMF orientation occurs most frequently in the upstream region of the Martian bow shock.We also conclude that these variabilities are not artefacts of temporal coverage biases in MAVEN sampling.Our results demonstrate that whereas IMF cone angle strongly influences the occurrence of PCWs,IMF cone angle may also weakly modulate their amplitudes in the upstream region of Mars.
文摘The present issue of Earth and Planetary Physics is dedicated to the near-space neutral and plasma environments of Mars.The issue includes nine papers that present new results on the properties of the Martian exosphere,ionosphere,and magnetosphere,from both observational and modeling points of view.Due to the similarity between the two objects,the issue also includes two additional papers on the near-Venus plasma environment.
基金supported by the National Natural Science Foundation of China (41525016, 41525015, 41661164034, 41621063)the National Important Basic Research Project (2011CB811405)supported by the Thousand Young Talents Program of China
文摘The Venusian dayside ionosphere, similar to other planetary ionospheres, is produced primarily by ionization of its neutral upper atmosphere due to solar extreme ultraviolet (EUV) radiation. It has become clear that the expansion of the ionosphere may be strongly controlled by the EUV level, as exhibited in data collected by the Pioneer Venus Orbiter (PVO) during one solar cycle (1978 1992). However, the EUV-dependence of the Venusian dayside ionopause altitude, which defines the outer boundary of the ionosphere, remains obscure because the PVO crossed the dayside ionopause only during the solar maximum;its periapsis lifted too high during the solar minimum. Recently, during the period 2006 2014, which included the longest and quietest solar minimum of the past several decades, Venus Express (VEX) provided measurements of the photoelectron boundary (PEB) over the northern high-latitude region. Since the photoelectron boundary is closely related to the ionopause, we have an opportunity to analyze the EUV effect on the dayside ionopause by combining PVO and VEX observations. We have evaluated and then reduced the orbit bias effect in data from both PVO and VEX, and then used the results to derive a relationship between solar EUV level and the dayside ionopause altitude. We find that the dayside ionopause altitude increases as the solar EUV level increases, which is consistent with theoretical expectations.
基金supported by the National Science Foundation of China (41525016,41474155,41661164034,41621004)Macao FDCT grant 001/2016/AFJsupported by the Thousand Young Talents Program of China
文摘The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth's interior process is contentious. In the past several decades,space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate(>5 ka). Here, we propose to take the advantage of " space-diversity" to build a " generalized planetary space family", to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets' evolution.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.41621004,41774188)Y.W.was also supported by the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(Grant No.IGGCAS-201904)+1 种基金R.N.M.was supported by the Key Research Program of the Institute of Geology&Geophysics,Chinese Academy of Sciences(Grant No.IGGCAS-201905)the National Natural Science Foundation of China(Grant No.41888101).
文摘The strength and configuration of the geomagnetic field control the average shape of the magnetosphere.The pure dipole assumption and the virtual dipole moment(VDM),determined by individual records,have been widely adopted to evaluate the strength of the geomagnetic field in geological time.However,such an assumption might not be valid during geomagnetic transitions,such as reversals and excursions.The traditional spherical harmonic modeling of the geomagnetic field could be difficult to implement because accurate global records are lacking.Here,we report that an empirical relationship exists between the ratio of the VDM to the true axial dipole moment(VDM/ADM)and the ratio of the power of the axial dipole to that of the non-axial dipole(AD/NAD)based on a new method utilizing globally distributed inclination records.The root mean square global deviation of inclination(RMSΔI)to the standard inclination distribution of the AD was fitted to the AD/NAD with a cubic polynomial by utilizing a large number of geodynamo simulations.Tests with geomagnetic field models showed that the AD/NAD derived from the RMSΔI agreed well with that calculated by using the Gauss coefficients,and the estimated ADM was consistent with the true value.Finally,the application of volcanic records during the Laschamp excursion showed the VDM might overestimate the ADM by a factor of 3.Our new method will be useful in future studies that characterize the configuration of the geomagnetic field and the strength of the axial dipole.
基金supported by B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)National Natural Science Foundation of China(42274223)Youth Innovation Promotion Association CAS.
文摘The 5th Youth Scientist Forum of Planetary Science(YSFPS)took place from March 25 to 29,2023,in Sanya,a picturesque coastal city in the Hainan Province of southern China.This forum,one of China’s largest gatherings of its kind,experienced over 1,000 participants from domestic universities and research institutes discussing advancements in a variety of topics,including the surface,atmosphere,interior,core of planets,exoplanet exploration,asteroids,and comets(as shown in Figure 1A).One of the international hot topics in this meeting was lunar science research.With the return of lunar samples from the Chang’e-5 mission,scientists have immediately carried out various studies,forming new understandings about the moon’s evolution and raising new questions.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA17010201)the National Natural Science Foundation of China(Grant Nos.42074207,42104171)+3 种基金the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant Nos.IGGCAS-201904,IGGCAS-202102)the Key Research Program of Chinese Academy of Sciences(Grant No.ZDBS-SSW-TLC00103)supported by the Thousand Young Talents Program of Chinasupported by the Youth Innovation Promotion Association of CAS(Grant No.2021064)。
文摘On the great journey to Mars,China’s first planetary exploration mission,the Tianwen-1 came within 26 million kilometers of Mars from 31 October 2020 to 25 January 2021 and was getting closer to its destination,the red planet,in search of answers to the cataclysmic climate change that occurred in Martian history.Both the escape of the Martian atmosphere and the loss of surface water were firmly influenced by solar activities.Tianwen-1 provided a unique chance to depict the solar wind streams between Earth and Mars during the minimum of Solar Cycle 25.During the three-month cruise phase of Tianwen-1,the solar wind flows were successively observed at Earth,Tianwen-1,and Mars.After the field of view correction and noise reduction,the solar wind velocity and density measured by Tianwen-1 show good agreement with those at Earth and Mars.The results indicate that the performance of the ion analyzer onboard the Tianwen-1 orbiter is reliable and stable.It is worth looking forward to the joint observations of ion escape with other Mars probes in the following Martian years.
基金supported by Thousand Young Talents Program of China, National Natural Science Foundation of China(41525016, 41474155, 41661164034 and 41621004)German Grant WO910/3-1 within the Planetary Magnetism Priority Program of the Deutsche Forschungsgemeinschaft and through Grant 50QM0801 of the German Aerospace Agency
文摘As an Earth-like planet Venus probably had a primordial dipole field for several million years after formation of the planet.Since this dipole field eventually vanished the ionosphere of Venus has been exposed to the solar wind.The solar wind is shocked near Venus,and then scavenges the ionospheric particles through the magnetosheath and the magnetotail.The escape rate of oxygen ions(O^+)estimated from spacecraft observations over the past several decades has manifested its importance for the evolution of planetary habitability,considering the accumulated effect over the history of Venus.However,all the previous observations were made in the shocked solar wind and/or inside the wake,though some simulations showed that unshocked solar wind can also ablate O^+ions.Here we report Venus Express observations of O^+ions in the unshocked solar wind during the solar minimum.The observations suggest that these O^+ions are accelerated by the unshocked solar wind through pickup processes.The estimated O^+escape rate,2.1×10^(24) ions/s,is comparable to those measured in the shocked solar wind and the wake.This escape rate could result in about 2 cm global water loss over 4.5 billion years.Our results suggest that the atmospheric loss at unmagnetized planets is significantly underestimated by previous observations,and thus we can emphasize the importance of an Earth-like dipole for planetary habitability.
基金supported by the National Natural Science Foundation of China(Grant No.42241106)。
文摘Extensive research efforts have revealed that the Martian dust storms can perturb the upper atmospheric condition and as a consequence,enhance plasma density and photoelectron flux in the ionosphere.However,previous observational studies of the Martian dust storm impacts have been restricted to regions below 400 km,which limits our understanding of the Martian dust storm effects in the upper ionosphere and magnetosphere.Here,based on the suprathermal electron measurements made by the Solar Wind Electron Analyzer onboard the Mars Atmosphere and Volatile Evolution,we identify with an automatic procedure the occurrences of all photoelectron boundary(PEB)crossings at solar zenith angle below 120°(with a dust-free median altitude of about 600 km).Using the dayside PEB as a proxy of the upper ionospheric and magnetospheric condition,we analyze the variations of the PEB altitude during the 2018 global dust storm(GDS)of Mars Year 34(MY34)and compare them with the period in MY33 when there was no global dust storm.We conclude that the column dust optical depth(CDOD)emerges as one of the main driving factors for PEB altitude variations during the GDS.Our analysis implies that the GDS can affect the Martian upper atmosphere and ionosphere over considerable distances and extended time scales.